    Network Working Group                                      S. Williamson
    Request for Comments: 2167                                    M. Kosters
    Obsoletes: RFC 1714                                            D. Blacka
    Category: Informational                                         J. Singh
                                                                 K. Zeilstra
                                                     Network Solutions, Inc.
                                                                   June 1997

                     Referral Whois (RWhois) Protocol V1.5

    Status of this Memo

       This memo provides information for the Internet community.  This memo
       does not specify an Internet standard of any kind.  Distribution of
       this memo is unlimited.

    Abstract

       This memo describes Version 1.5 of the client/server interaction of
       RWhois.  RWhois provides a distributed system for the discovery,
       retrieval, and maintenance of directory information. This system is
       primarily hierarchical by design. It allows for the deterministic
       routing of a query based on hierarchical tags, referring the user
       closer to the maintainer of the information. While RWhois can be
       considered a generic directory services protocol, it distinguishes
       itself from other protocols by providing an integrated, hierarchical
       architecture and query routing mechanism.

    1. Introduction

       Early in the development of the ARPANET, the SRI-NIC established a
       centralized Whois database that provided host and network information
       about the systems connected to the network and the electronic mail
       (email) addresses of the users on those systems [RFC 954]. The
       ARPANET experiment evolved into a global network, the Internet, with
       countless people and hundreds of thousands of end systems. The sheer
       size and effort needed to maintain a centralized database
       necessitates an alternate, decentralized approach to storing and
       retrieving this information.

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       The original Whois function was to be a central directory of
       resources and people on ARPANET. However, it could not adequately
       meet the needs of the expanded Internet. RWhois extends and enhances
       the Whois concept in a hierarchical and scaleable fashion. In
       accordance with this, RWhois focuses primarily on the distribution of
       "network objects", or the data representing Internet resources or
       people, and uses the inherently hierarchical nature of these network
       objects (domain names, Internet Protocol (IP) networks, email
       addresses) to more accurately discover the requested information.

       RWhois synthesizes concepts from other, established Internet
       protocols. The RWhois protocol and architecture derive a great deal
       of structure from the Domain Name System (DNS) [RFC 1034] and borrow
       directory service concepts from other directory service efforts,
       primarily [X.500]. The protocol is also influenced by earlier
       established Internet protocols, such as the Simple Mail Transport
       Protocol (SMTP) [RFC 821].

       This RWhois specification defines both a directory access protocol
       and a directory architecture. The directory access protocol
       specifically describes the syntax of the client/server interaction.
       It describes how an RWhois client can search for data on an RWhois
       server, or how the client can modify data on the server. It also
       describes how the server is to interpret input from the client, and
       how the client should interpret the results returned by the server.
       The architecture portion of this document describes the conceptual
       framework behind the RWhois protocol. It details the concepts upon
       which the protocol is based and describes its structural elements.
       The protocol implements the architecture.

       This document uses language like SHOULD and SHALL that have special
       meaning as specified in "Key words for use in RFCs to Indicate
       Requirement Levels". [RFC2119]

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    2. Architecture

    2.1 Overview

       As a directory service, RWhois is a distributed database, where data
       is split across multiple servers to keep database sizes manageable.
       The architecture portion of this document details the concepts upon
       which the protocol is based and describes its structural elements.
       Specifically, the architecture is concerned with how the data is
       split across the different servers. The basis of this splitting is
       the lexically hierarchical label (or tag), which is a text string
       whose position in a hierarchy can be determined from the structure of
       the string itself.

       All data can follow some sort of hierarchy, even if the hierarchy
       seems somewhat arbitrary. For example, person names can be arranged
       into hierarchical groups via geography. If all the people in
       particular towns are grouped into town groups, then all of the town
       groups can be grouped into state (or province) groups, and then all
       of the state groups can be grouped into a country group. Then, a
       particular name would belong in a town group, a state group, and a
       country group. However, just given a name, it would be impossible to
       determine where in the hierarchy it belongs.  Therefore, a person
       name is not lexically hierarchical.

       However, there are certain types of data whose position in the
       hierarchy can be determined by deciphering the data itself, for
       example, phone numbers. A phone number is grouped according to
       country code, area code, local exchange, and local extension. By
       looking at a phone number, it is possible to determine to which of
       all these groups the number belongs:  1-303-555-2367 is in country
       code 1, area code 303, local exchange 555, and has a local extension
       of 2367. Therefore, a phone number is lexically hierarchical.

       On the Internet, two such types of data are widely used: domain names
       and IP networks. Domain names are organized via a label-dot system,
       reading from a more specific label to a more general label left to
       right; for example, war.west.netsol.com is a part of west.netsol.com,
       which is a part of netsol.com, which is a part of com. IP networks
       are also lexically hierarchical labels using the Classless Inter-
       Domain Routing (CIDR) notation, but their hierarchy is not easily
       determined with simple text manipulation; for example, 198.41.0.0/22
       is a part of 198.41.0.0/16, which is a part of 198.40.0.0/15.
       Instead, an IP network's hierarchy is determined by converting the
       network to binary notation and applying successively shorter bit
       masks.

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       It is important to note that, while very little real data is
       lexically hierarchical in nature, people often create label systems
       (or namespaces) to help manage the data and provide an element of
       uniqueness, for example, Social Security Numbers, ISBNs, or the Dewey
       Decimal System. RWhois leverages lexically hierarchical labels,
       domain names and IP networks, for its data splitting using the
       concepts of authority areas and referrals. An authority area is
       associated with an RWhois server and a lexically hierarchical label,
       which is considered to be its name. An authority area is a piece of
       the distributed database that speaks with authority about its
       assigned part of the hierarchy. All data associated with a particular
       lexically hierarchical tag should be located within that authority
       area's database. Authority areas are further explained in Section
       2.4.

       RWhois directs clients toward the appropriate authority area by
       generating referrals. Referrals are pointers to other servers that
       are presumed to be closer to the desired data. The client uses this
       referral to contact the next server and ask the same question. The
       next server may respond with data, an error, or another referral (or
       referrals). By following this chain of referrals, the client will
       eventually reach the server with the appropriate authority area. In
       the RWhois architecture, referrals are generated by identifying a
       lexically hierarchical label and deciphering the label to determine
       the next server. Referrals are further explained in Section 2.5.

       When a number of RWhois servers containing authority areas are
       brought on line and informed about each other, they form an RWhois
       tree. The tree has a root authority area, which is the group that
       contains all other groups.  The root authority area must keep
       pointers to the servers and authority areas that form the first level
       of the hierarchy. The authority areas in the first level of the
       hierarchy are then responsible for keeping pointers to the authority
       areas below them and for keeping a pointer to the root.

    2.2 Design Philosophy

       The design goals for the RWhois protocol are as follows.

          * It should be a directory access protocol. The server should be
            able to access and update the data residing on it.
          * It should facilitate query routing. An unresolved query should
            be redirected to a server that is presumed to be closer to the
            desired data.
          * It should enable data replication. The server should be able to
            duplicate its data on another server.
          * The server should be lightweight and delegate more functions to
            the client.

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       The concepts used to achieve these design goals are explained in the
       remaining document.

    2.3 Schema Model

       As a directory service, RWhois uses various database schema to store
       and represent data. Schema, in this document, has two definitions.
       First, it refers to the entire structure of a database, all the
       tables and fields forming a complete database. When schema is used in
       this context, it is called the "database schema". Database schema
       consists of attributes, classes, and objects. Schema may also refer
       to a single piece of the database, a single table with fields. When
       schema is used in this context, it is just called "schema" or it is
       preceded by the name of the particular piece: contact schema or
       domain schema, for example. In this usage, schema is equivalent to
       "class", defined below.

       There is no standard database schema in the RWhois architecture. Each
       authority area is presumed to be able to define its own local schema.
       However, an authority area that is part of a larger RWhois tree is
       expected to have some part of its schema pertain to the lexically
       hierarchical label upon which the RWhois tree is based. An authority
       area schema may not change throughout much of an RWhois tree.

    2.3.1 Attributes

       An attribute is a named field and is the smallest typed unit in the
       database schema. It is equivalent to a relational database's field.
       An attribute is not considered to be data by itself; it is simply
       used to give data a type. When a piece of data has been typed by an
       attribute, it is typically referred to as a value and is represented
       as an attribute-value pair. The RWhois syntax for the attribute-value
       pair is to separate them with a colon, for example:

       First-Name:Bill

       Attributes have a number of properties, some mandated by the RWhois
       protocol and some that are implementation dependent. These properties
       are usually a reflection of the database system used by the server.
       The following is a list of the protocol-mandated properties and their
       descriptions.

        Attribute    This is the name of the attribute.

        Description  This is a natural language description of the
                     attribute.

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        Type         This is a parameter that broadly indicates the use
                     of the attribute to the protocol. There are three
                     standard types:  TEXT, ID, and SEE-ALSO. The default is
                     TEXT, which indicates that the value is a text string.
                     ID indicates that the attribute contains the ID of
                     another RWhois object. This type of attribute is used
                     for database normalization.  SEE-ALSO indicates that
                     the attribute contains a pointer (a Uniform Resource
                     Identifier (URI)) to some other kind of external data;
                     for example, a World Wide Web page or FTP site.

        Format       This is an interpretable string that describes the
                     acceptance format of the value. The server (and
                     optionally the client) should match the value to the
                     format string to determine if the value is acceptable.
                     The format of this property is a keyword indicating the
                     syntax of the format string, followed by a colon,
                     followed by the format string itself. Currently, the
                     only keyword recognized is "re" for POSIX.2 extended
                     regular expressions.

        Indexed      This is a true or false flag indicating that this
                     attribute should be indexed (and therefore able to be
                     searched).

        Required     This is a true or false flag indicating that this
                     attribute must have a value in an instance of the
                     class.

        Multi-Line   This is a true or false flag indicating that this
                     attribute may have multiple instances in a class, but
                     all of the instances are to be considered as multiple
                     lines of the same attribute instance. This allows
                     normal line terminators to terminate values.

        Repeatable   This is a true or false flag indicating that there may
                     be multiple instances of this attribute in a class and
                     each instance is to be interpreted as a separate
                     instance (in contrast to Multi-Line). This flag is
                     mutually exclusive with Multi-Line: if Multi-Line is
                     true, then Repeatable must be false and vice versa.

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        Primary      This is a true or false flag that indicates that this
                     attribute is a primary key. If more than one attribute
                     in a class is marked as primary, then these attributes
                     together form a single primary key. The primary key is
                     intended to be used to force uniqueness among class
                     instances. Therefore, there can be only one instance of
                     a primary key in a database. The Primary flag implies
                     that the attribute is also required.

        Hierarchical This is a true or false flag that indicates that this
                     attribute is lexically hierarchical.

        Private      This is a true or false flag that indicates whether or
                     not this attribute is private (that is, publicly not
                     viewable).  It defaults to false. If it is true, then
                     only the clients that satisfy the
                     authentication/encryption requirements of a guardian
                     (described below) are able to view the attribute-value
                     pair.

    2.3.2 Class

       A class is a collection of attributes; it is a structure, not data.
       The concept is equivalent to that of a relational database table. It
       is also equivalent to the second definition of schema, above.

       A class also has some properties that are sometimes referred to as
       its "meta" information. These properties are listed below.

        Version     This is a time/date stamp that is used to quickly detect
                    when a class definition has been changed.

        Description This is a natural language description of the class.

    2.3.3 Object

       An object is an instance of a class. It is data with a type of
       <class>.

    2.3.4 Base Class

       While RWhois does not have or advocate using a specific, standardized
       schema, it does impose a few requirements. It requires that all
       defined classes inherit attributes from a particular base class (or
       base schema).  The RWhois specification does not require the actual
       implementation of inheritance. Instead, all classes must include the
       attributes defined in the base class.

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       The base class has the following attributes.

        Class-Name    This attribute contains the name of the class to which
                      the object belongs. It is the type of the object
                      itself. It is of type TEXT and is required.

        Auth-Area     This attribute contains the name of the authority area
                      to which the object belongs. It, along with Class-
                      Name, definitively defines the type of the object. It
                      is of type TEXT and is required.

        ID            This attribute is a universal identifier for the
                      object. It is formed by choosing a string that is
                      unique within an authority area and appending the
                      authority area to it, separating the local string from
                      the authority area name with a period. The only
                      restrictions on the local string are that it must be
                      unique within the authority area and not contain the
                      period character. This attribute is hierarchical in
                      nature. It is always generated by the server (for
                      example, during a register operation). It is of type
                      TEXT and is required.

        Updated       This attribute is a time/date stamp that indicates the
                      time of last modification of the object. It is both
                      informational and a form of record locking. It
                      prevents two clients from modifying the same object at
                      the same time. It is of type TEXT and is required.

        Guardian      This attribute is a link to a guardian object
                      (described below). Its value is the ID of a guardian
                      object. It is of type ID and is optional. It is
                      repeatable, since an object may have multiple
                      guardians.

        Private      This attribute is a true or false flag that indicates
                      whether or not an object is private (that is, publicly
                      not viewable). It defaults to false. If it is true,
                      then only the clients that satisfy the
                      authentication/encryption requirements of one of the
                      object's guardians are able to view the object. If the
                      object is publicly viewable, then the Private
                      attribute property of each of its attributes still
                      applies.

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        TTL           This attribute is the "time-to-live" of a given
                      object. It is included only if an object has a
                      different time-to-live than the default given in the
                      Start of Authority information. Its value is specified
                      in seconds. It is of type TEXT and is optional.

       The RWhois specification defines two standard classes that should be
       included in all implementations: the referral and guardian classes.

    2.3.5 Referral Class

       The referral class is defined to hold referral information (typically
       for link referrals). It consists of attributes defined as part of the
       base class, the protocol-specific attributes described below, and any
       installation-specific attributes.

        Referred-Auth-Area This attribute contains the name of the authority
                           area to which the referral points. It is used as
                           a search key during the query routing. It is of
                           type TEXT and is required. It is repeatable,
                           since referrals can point to servers hosting more
                           than one authority area.

        Referral           This attribute contains the referral itself. It
                           is an RWhois URL. It is of type TEXT and is
                           required. It is repeatable, since more than one
                           server can host a Referred-Auth-Area.

    2.3.6 Guardian Class

       The guardian class is defined to hold security information. The
       fundamental concept behind the guardian class is that an object (or
       another structure) is "guarded" by containing a pointer to a guardian
       object [Guardian]. To modify, delete, or possibly view the guarded
       object, the authentication (or encryption, or both) scheme must be
       satisfied. Guardians are intended to not have rank: if an object is
       guarded by more than one guardian object, satisfying any one of those
       guardians is sufficient. A guardian object that does not have any
       Guardian attribute linking it to other guardians guards itself. That
       is, the authentication scheme in the guardian object itself must be
       satisfied to modify, delete, or possibly view it.

       Guardian objects are typically linked to actual database objects with
       the Guardian attribute found in the base class. However, a guardian
       may also be linked to an entire authority area, in which case the
       guardian becomes implicitly linked to all of the objects contained
       within the authority area.

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       The guardian class consists of the base class, the protocol-specific
       attributes described below, and any installation-specific attributes.

        Guard-Scheme This attribute contains a keyword indicating the
                     authentication methodology. Its value must be
                     understood by both the client and server, and its value
                     dictates the contents of the Guard-Info attribute. It
                     is of type TEXT and is required.

        Guard-Info   This attribute contains that data that is used by the
                     Guard-Scheme to verify the authentication. Its actual
                     format is dictated by the Guard-Scheme, for example, it
                     could contain a password or Pretty Good Privacy (PGP)
                     public key id [RFC 1991]. For security reasons, it
                     should not be displayed, and its Private attribute
                     property should be set to true. It is of type TEXT and
                     is required.

    2.4 Authority Areas

       The concept of authority areas is pivotal to the RWhois architecture.
       When an RWhois tree is created for a particular lexically
       hierarchical namespace, the different pieces of the hierarchy are
       mapped to authority areas. The most important concept behind an
       authority area is the ability for a portion of the RWhois tree to
       definitively control that portion of the hierarchy. This means that
       an authority area is able to state whether or not a hierarchical tag
       is in the whole RWhois tree. It does this either by returning the
       object containing this tag, returning a referral to a sub-authority
       area, or returning a response indicating that no objects were found.

       This structure enables efficient routing of queries based on the
       hierarchical label to the piece of the hierarchy responsible for it.
       For example, in the domain name namespace as served by RWhois, the
       root of the tree would be an authority area named ".", which would
       delegate a "us" sub-authority area, which would delegate "va", "co",
       "md", and "ca" authority areas, and so forth. When the server with
       the "va.us" authority area is asked about "loudoun.va.us", it will be
       able to authoritatively state that either no "loudoun.va.us" exists
       or it will provide an object for or a referral to "loudoun.va.us".
       Further, if the server is asked about "howard.md.us", it cannot
       answer authoritatively, so it must provide a referral to its
       hierarchical parent ("us" or the root).

       This use of authority area strongly indicates where data should be
       stored within an RWhois tree. Because RWhois uses a specific query
       routing model, data needs to be placed under the proper authority
       area. It is certainly possible to place a piece of data under the

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       wrong authority area, for example, putting an object for
       "howard.md.us" under the "va.us" authority area. In such cases, the
       data is considered to be misplaced and unable to be found within the
       RWhois tree. However, while data should be placed under the lowest
       (most specific) authority area, it is also possible that it could be
       placed in a higher (least specific) authority area, for example,
       putting an object for "loudoun.va.us" under the "us" authority. This
       may be acceptable since, in most cases, the data would be able to be
       found.

       In addition to controlling a part of an RWhois hierarchy, an
       authority area is considered to be autonomous. Each authority area is
       treated as a separate database by the protocol. However, it is
       recommended that an authority area share some core schema with the
       rest of the RWhois tree for interoperability reasons. Each authority
       area, however, is not bound by the database schema of its
       hierarchical parent or by any of its sub-authority areas.

    2.5 Query Routing

       RWhois is not only a directory access protocol but it can also route
       queries. Routing a query involves redirecting the query to another
       server that is presumed to be closer to the desired data. To route a
       query, the server first determines the location of the next server.
       It then either forwards the query to that server and returns the
       result to the client or returns the location of that server to the
       client. The location of the server must contain its host name (or IP
       address), port number, and authority area.

       The location of the server to which a query is routed is called a
       referral.  There are two types of referrals: punt and link referrals.
       A punt referral is a pointer to a server that is further up an RWhois
       tree, and a link referral is a pointer to a server that is further
       down the tree. For example, in Figure 1, when the server for the
       "va.us" authority area routes a query up to the server for the "us"
       authority area, it generates a punt referral. Alternatively, when it
       routes a query down to the server for the "loudon.va.us" authority
       area, it generates a link referral.

       Query routing depends on whether or not the search value in a query
       is lexically hierarchical. If the search value is hierarchical, the
       server can generate punt or link referrals using the association of
       authority areas with lexically hierarchical labels. Otherwise, the
       server may send the query to a special index server that gathers the
       indexing information for both hierarchical and non-hierarchical data
       from the directory servers and returns referrals to these servers
       [CIP]. If the server receives one or more referrals from the index
       server, it should return them to the client.

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       It is important to note that the server may route a query whether it
       could resolve the query or not. Even if a query has been resolved
       locally, the server may also return referrals to the client by
       sending the query to the index server. For example, if the server for
       the "com" authority area receives the "domain Org-Name=IBM" query, it
       may return all the domain objects for IBM within the "com" authority
       area. In addition, it may also return referrals to the server for the
       "nl" authority area if that server contains domain objects for IBM in
       the Netherlands and has fed the corresponding indexing information to
       the index server. This way the client can get back information for
       both "ibm.com" and "ibm.nl" domains.

    2.5.1 Query Routing Rules

       An RWhois server routes a query based on certain rules. The objective
       is to determine the location of a server to which to route the query.
       A query may contain one or more query terms. The query routing rules
       are applied on each query term until a referral is found. The rules
       are listed below.

          * Is the search value in the query term hierarchical? If not, go
            to the next query term.
          * Parse the hierarchical portion of the search value. Is it is
            within one of the authority areas? If not, go to the next query
            term.
          * Does the found authority area have any referral objects
            (instances of the referral class)? If not, return the "230 No
            objects found" error to the client.
          * Is the hierarchical portion of the search value within the
            Referred-Auth-Area attribute of one of the referral objects? If
            it is, return the value of the Referral attribute of the found
            referral object as a link referral to the client.
          * Are the search values of some of the query terms hierarchical
            but not within any of the authority areas? If they are, return a
            punt referral to the client.
          * Are the search values of all the query terms non-hierarchical?
            If they are, send the query to a special index server that
            gathers the indexing information for both hierarchical and non-
            hierarchical data from the directory servers and returns
            referrals to these servers. If the server receives one or more
            referrals from the index server, return them to the client.

       Note that there can be more than one referral returned to the client.
       These referrals may point to servers serving different authority
       areas. The client may follow them in any order.

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       The pseudo code for the above rules is:

       for each query term in the query
        if the search value in the query term is hierarchical
         if the search value is within one of the authority areas
           if the search value is within one of the referred authority areas
            the server sends link referral(s)
           else
            the server sends a "230 No objects found" error
           endif
         endif
        endif
       endfor

       if the search values of some of the query terms are hierarchical but
         not within any of the authority areas
        the server sends Punt referral(s)
       endif

       if the search values of all the query terms are non-hierarchical
        the server sends Referral(s) from an index server
       endif

    2.6 Data Replication

       An RWhois server can replicate (duplicate) data from another RWhois
       server on a per-authority area basis. Data replication makes the
       RWhois service more reliable. Further, it increases throughput by
       distributing queries to more than one server.

       There can be two types of servers serving an authority area: a master
       server and a slave server. A master server is where data is
       registered for an authority area. It answers authoritatively to
       queries in that authority area. There must be one and only one master
       server for an authority area. A master server is also called a
       primary server.

       A slave server is where data is replicated from the master server for
       an authority area. It also answers authoritatively to queries in that
       authority area. There may be one or more slave servers for an
       authority area. A slave server is also called a secondary server.
       Note that a slave server must not register data for an authority
       area.

       It is recommended that the master and slave servers for an authority
       area be geographically separate. Therefore, network unreachability at
       one site will not completely shut down the RWhois service for that
       authority area.

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    2.6.1 Data to Replicate

       In RWhois, data is replicated on a per-authority area basis. The
       smallest type of data a slave server can replicate is an attribute of
       a class.  Therefore, a slave server can replicate data for all the
       classes, some classes, or some attributes of some classes.

       The amount of data a slave server can replicate each time is either
       all of the data or the data that has changed since the last
       replication. The process of replicating all of the data is called
       complete replication. The process of replicating the data that has
       changed since the last replication is called incremental replication.

    2.6.2 Start Of Authority Variables

       Each authority area has some administrative variables, defined at the
       master server, to control data replication. These variables are
       called the Start Of Authority (SOA) variables. They are listed below.

        Serial-Number     This is the serial number of the data in an
                          authority area. The master server should update
                          this variable whenever the data in the authority
                          area is changed. Its value is a time/date stamp.

        Refresh-Interval  This is the time interval before a slave server
                          checks for complete replication. Its value is
                          specified in seconds.

        Increment-IntervalThis is the time interval before a slave server
                          checks for incremental replication. Its value is
                          specified in seconds.

        Retry-Interval    This is the time interval before a slave server
                          tries again to connect to a master server that
                          appears to be out-of-service. Its value is
                          specified in seconds.

        Time-To-Live      This is the default time to live for the data in
                          an authority area at a slave server. The slave
                          server should not answer authoritatively to
                          queries for such stale data. Its value is
                          specified in seconds.

        Admin-Contact     This is the email address of an individual or a
                          role account responsible for the data integrity in
                          an authority area at the master server.

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    RFC 2167                    RWhois Protocol                    June 1997

        Tech-Contact      This is the email address of an individual or a
                          role account responsible for the operation of the
                          master server for an authority area.

        Hostmaster        This is the email address of an individual or a
                          role account to whom email messages to update the
                          data in an authority area at the master server are
                          sent.

        Primary-Server    This is the location of the master server for an
                          authority area. Its value must contain both the
                          host name (or IP address) and port number of the
                          master server.

    3. Protocol

    3.1 Overview

       The above sections describe the directory service architecture based
       on the RWhois protocol. The remaining sections describe the syntax of
       the protocol; the sequence and syntax of the information exchanged
       between a server and a client. There are five types of information
       that may be exchanged during a client/server session: directive,
       response, query, result, and info.

    3.1.1 Directive

       A directive is a command that a client sends to a server to set a
       control parameter for the session, get the meta-information (class
       definitions and SOA information) about an authority area, or get the
       data in an authority area. The first character of a directive must be
       a "-". The server must support the "-rwhois" directive; all other
       directives are optional. The server must indicate in the banner which
       directives are implemented (see Section 3.1.9).

    3.1.2 Response

       A response is the information that a server returns to a client for a
       directive. It is comprised of one or more lines, and the last line
       always indicates the success or failure of the directive. The first
       character of each response line must be a "%". If a server runs a
       directive successfully, the last response line must be "%ok".
       Otherwise, it must be "%error <error-code> <error-text>". A line with
       the string "%ok" or "%error" in the first position must occur only
       once in a server response and must always be the last line. The
       server may send the "%info" response for special messages.

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       A client must understand the "%ok", "%error", and "%info" responses.
       The client must also understand directive specific responses, if it
       uses the related directives to communicate with the server. For
       example, if the client sends the "-schema" directive to the server,
       the client must understand the "%schema" response.

    3.1.3 Query

       A query is a command that a client sends to a server to access the
       data in an authority area. The first character of a query must not be
       a "-", since the server checks the first character of each command
       from a client to determine whether it is a directive or a query.

    3.1.4 Result

       A result is the information that a server returns to a client for a
       query.  It can be either the accessed data or referrals to other
       servers. It is comprised of one or more lines, and the last line
       always indicates the success or failure of the query. If a server
       returns either data or referrals for a query, the last result line
       must be "%ok". Otherwise, it must be "%error <error-code> <error-
       text>".

    3.1.5 Info

       An info message contains miscellaneous information that a server
       sends to a client. The server may use it to send special messages,
       for example a "message of the day" (MOTD), to the client. The first
       info line must be "%info on", and the last info line must be "%info
       off".

    3.1.6 Client/Server Session

       A typical RWhois client/server session has the following sequence of
       messages.

          * The client connects to the server.
          * The server returns a banner identifying its protocol versions
            and capabilities.
          * The client sends one or more directives to the server.
          * The server returns the response to each directive.
          * The client finally sends a query to the server.
          * The server returns the query results.
          * The server closes the connection, unless the client has directed
            it not to close the connection.

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    3.1.7 Examples

       This section gives some common examples of the client/server
       interaction.  The notation in the examples uses a prefix to indicate
       from where the information comes. A "C" indicates that the client
       sends the data to the server. An "S" indicates that the server sends
       the data to the client. The line is a comment when "#" is used. The
       space after the prefix is not part of the data.

       The following example illustrates a successful query.

       # The client connects to the server.
       # The server returns a banner identifying its protocol versions and
       # capabilities.
       S %rwhois V-1.5:00ffff:00 master.rwhois.net (Network Solutions V-1.5)
       # The client sends a directive to limit the number of search hits
       # to 20.
       C -limit 20
       # The server returns a successful response.
       S %ok
       # The client sends a query to search for rwhois.net domain.
       C domain rwhois.net
       # The server returns the data for rwhois.net domain.
       S domain:ID:dom-1.rwhois.net
       S domain:Auth-Area:rwhois.net
       S domain:Class-Name:domain
       S domain:Updated:19970107201111000
       S domain:Domain:rwhois.net
       S domain:Server;I:hst-1.rwhois.net
       S domain:Server;I:hst-2.rwhois.net
       S
       S %ok
       # The server closes the connection.

       The following example illustrates the link and punt referrals.

       # The client connects to the server.
       # The server returns a banner identifying its protocol versions and
       # capabilities.
       S %rwhois V-1.5:00ffff:00 master.rwhois.net (Network Solutions V-1.5)
       # The client sends a directive to hold the connection until it sends
       # a directive to close the connection.
       C -holdconnect on
       # The server returns a successful response.
       S %ok
       # The client sends a query to search for a.b.rwhois.net domain.
       C domain a.b.rwhois.net
       # The server returns a link referral to a server serving the

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       # b.rwhois.net authority area.
       S %referral rwhois://master.b.rwhois.net:4321/auth-area=b.rwhois.net
       S %ok
       # The client sends a query to search for internic.net domain.
       C domain internic.net
       # The server returns a punt referral to a server serving the root
       # authority area.
       S %referral rwhois://rs.internic.net:4321/auth-area=.
       S %ok
       # The client sends a directive to close the connection.
       C -quit
       S %ok
       # The server closes the connection.

       The following example illustrates a query error.

       # The client connects to the server.
       # The server returns a banner identifying its protocol versions and
       # capabilities.
       S %rwhois V-1.5:00ffff:00 master.rwhois.net (Network Solutions V-1.5)
       # The client sends a query to search for c.rwhois.net domain.
       C domain c.rwhois.net
       # The server returns an error, since neither data nor referrals for
       # c.rwhois.net domain are found within the rwhois.net authority area.
       S %error 230 No objects found
       # The server closes the connection.

    3.1.8 Notation

       The following sections use the Augmented Backus-Naur Form (ABNF)
       notation to describe the syntax of the protocol. For further
       information, see Section 2 of [RFC822]. The notation in the examples
       uses a prefix to indicate from where the information comes. A "C"
       indicates that the client sends the data to the server. An "S"
       indicates that the server sends the data to the client. The line is a
       comment when "#" is used. The space after the prefix is not part of
       the data.

    3.1.9 General ABNF definitions

       Lexical Tokens

       alpha = "a".."z" / "A".."Z"
       digit = "0".."9"
       hex-digit = digit / "a".."f" / "A".. "F"
       id-char = alpha / digit / "_" / "-"
       any-char = <ASCII 1..255,
                  except LF (linefeed) and CR (carriage return)>

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       dns-char = alpha / digit / "-"
       email-char = <see [RFC 822]>
       space = " "
       tab = <ASCII TAB (tab)>
       lf = <ASCII LF (linefeed)>
       cr = <ASCII CR (carriage return)>
       crlf = cr lf

       Grammar

       year = 4digit
       month = 2digit
       day = 2digit
       hour = 2digit
       minute = 2digit
       second = 2digit
       milli-second = 3digit
       host-name = dns-char *(dns-char / ".")
       ip-address = 1*3digit "." 1*3digit "." 1*3digit "." 1*3digit
       email = 1*email-char "@" host-name
       authority-area = (dns-char / ".") *(dns-char / "." / "/")
       object-id = 1*id-char "." authority-area
       host-port = (host-name / ip-address) ":" 1*5digit
       class-name = 1*id-char
       attribute-name = 1*id-char
       attribute-value = 1*any-char
       time-stamp = year month day hour minute second milli-second
       on-off = "on" / "off"

       Note that the time-stamp must be in the Greenwich Mean Time (GMT)
       time zone.  Also note that since in the above any-char is 1..255
       ASCII that the RWhois protocol is an 8 bit protocol.

       Response

       The general response for every directive and query is either "%ok" or
       "%error". In addition, a "%info" response may be sent.

       response = ok-response crlf / error-response crlf / info-response
       ok-response = "%ok"
       error-response = "%error" space error-code space error-text
       error-code = 3digit
       error-text = 1*any-char
       info-response = "%info" space "on" crlf *(*any-char crlf) "%info"
               space "off" crlf

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       Banner

       The server must send a banner to the client when the connection is
       opened.  The banner contains the version(s) of the protocol the
       server supports and a capability ID of encoded bit flags that
       indicates which directives are implemented. If the server supports
       more than one version of the protocol, the lowest-numbered version
       must be specified first. The bits in extra-id are reserved for future
       use. The end of the banner should contain a free-form string
       indicating the name of the server implementation. A server must
       support at least one version of the protocol, and may accept more
       versions for compatibility reasons.

       rwhois-banner = "%rwhois" space version-list space host-name
             [space implementation] crlf
       version-list = version *("," version)
       version = version-number [":" capability-id]
               / "V-1.5" ":" capability-id
       version-number = "V-" 1*digit "." 1*digit
       capability-id = response-id ":" extra-id
       response-id = 6hex-digit
       extra-id = 2hex-digit
       implementation = 1*any-char

       Protocol

       The entire RWhois protocol can be defined as a series of directives,
       responses, queries, and results.

       rwhois-protocol = client-sends / server-returns
       client-sends = *(directives / rwhois-query)
       server-returns = *(responses / rwhois-query-result)

    3.2 Required Directives

       The server must implement the following directives.

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    3.2.1 rwhois

       Description

       The "-rwhois" directive may be issued by the client at the start of
       every session . It tells the server which version of the protocol the
       client can handle. The server must respond with a banner containing
       the protocol version and directives it implements. This banner is the
       same banner that is sent by the server when the connection is opened,
       except that the server must indicate only one version number. The
       banner issued when opening a connection may contain more than one
       version number. The directive flags are encoded into three octets,
       which are described in Appendix D.

       ABNF

       rwhois-dir = "-rwhois" space version-number [space implementation]
                    crlf
       rwhois-response = "%rwhois" space version space host-name
               [space implementation] crlf

       Errors

       300 Not compatible with version
       338 Invalid directive syntax

       Examples

       # When a connection is opened, the server issues the banner.
       S %rwhois V-1.0,V-1.5:00ffff:00 rs.internic.net (NSI Server 1.5.4)
       # The client sends the rwhois directive.
       C -rwhois V-1.5 NSI Client 1.2.3
       S %rwhois V-1.5:00ffff:00 rs.internic.net (NSI Server 1.5.4)
       S %ok

    3.3 Optional Directives

       The server should implement the following directives.

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    3.3.1 class

       Description

       The "-class" directive can be used by the client to get the meta-
       information for one or more classes in an authority area. The
       response must contain the description and version number of each
       specified class and may be expanded in the future with additional
       attributes. When no class name is given, the server must return the
       meta-information for all the classes in the authority area. Every
       class record must end with an empty "%class" line.

       ABNF

       class-dir = "-class" space authority-area *(space class-name) crlf
       class-response = *class-record response
       class-record = *class-line "%class" crlf
       class-line = "%class" space class-name ":" "description" ":"
                    1*any-char crlf
          / "%class" space class-name ":" "version" ":" time-stamp crlf
          / "%class" space class-name ":" meta-field ":" meta-value crlf
       meta-field = 1*id-char
       meta-value = 1*any-char

       The following fields are required.

        meta-field   meta-value  Description

        description  1*any-char  Class description.
                               Time/date stamp indicating version of class,

        version      time-stamp  must be updated after class definition is
                                 changed.

       Errors

       338 Invalid directive syntax
       340 Invalid authority area
       341 Invalid class
       400 Directive not available
       401 Not authorized for directive

       Examples

       C -class rwhois.net domain host
       S %class domain:description:Domain information
       S %class domain:version:19970103101232000
       S %class

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       S %class host:description:Host information
       S %class host:version:19970214213241000
       S %class
       S %ok

    3.3.2 directive

       Description

       The "-directive" directive can be used by the client to get
       information about the directives that the server supports. The
       response must contain the name and description of each specified
       directive and may be expanded in the future with additional
       attributes. When no directive name is given, the server must return
       information about all the directives. Every directive record must end
       with an empty "%directive" line.

       ABNF

       directive-dir = "-directive" *(space directive-name) crlf
       directive-name = 1*id-char
       directive-response = *directive-record response
       directive-record = "%directive" space "directive" ":" directive-name
                          crlf *directive-line "%directive" crlf
       directive-line = "%directive" space "description" ":" 1*any-char crlf
               / "%directive" space attribute-name ":" attribute-value crlf

       Errors

       338 Invalid directive syntax
       400 Directive not available
       401 Not authorized for directive

       Examples

       Without parameters:

       C -directive
       S %directive directive:rwhois
       S %directive description:RWhois directive
       S %directive
       S %directive directive:quit
       S %directive description:Quit connection
       S %directive
       S %ok

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       With parameters:

       C -directive quit
       S %directive directive:quit
       S %directive description:Quit connection
       S %directive
       S %ok

    3.3.3 display

       Description

       By default, the server uses the dump format for the output of a query
       result. The output format can be changed with the "-display"
       directive.  When no parameter is given, the server must list all the
       display formats it supports. Every display record must end with an
       empty "%display" line.

       Currently, only the dump format is standard and must be supported by
       the server. Other output formats may be added in the future. See
       Section 3.4 for the definition of the dump format.

       ABNF

       display-dir = "-display" crlf
           / "-display" space display-name crlf
       display-name = 1*id-char
       display-response = *(display-record) response
       display-record = "%display" space "name" ":" display-name crlf
       *display-line "%display" crlf
       display-line = "%display" space attribute-name ":"
                      attribute-value crlf

       Errors

       338 Invalid directive syntax
       400 Directive not available
       401 Not authorized for directive
       436 Invalid display format

       Examples

       # Get the available display formats.
       C -display
       S %display name:dump
       S %display
       S %ok

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       # Change the active display format.
       C -display dump
       S %ok

    3.3.4 forward

       Description

       The "-forward" directive instructs the server to follow all the
       referrals and return the results to the client. This directive can be
       used to run an RWhois server as a proxy server. The default value
       must be "off". When the value is set to "on", the server must not
       return referrals.

       ABNF

       forward-dir = "-forward" space on-off crlf
       forward-response = response

       Errors

       338 Invalid directive syntax
       400 Directive not available
       401 Not authorized for directive

       Examples

       C -forward on
       S %ok

       C -forward off
       S %ok

    3.3.5 holdconnect

       Description

       Normally, the server closes the connection after each query. This
       behavior is controlled by the holdconnect state, which can be changed
       with the "-holdconnect" directive. When the holdconnect state is set
       to "off", the server must close the connection after a query; when it
       is set to "on", the server must not close the connection after a
       query. By default, the holdconnect state must be set to "off" for
       each connection.

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       ABNF

       holdconnect-dir = "-holdconnect" space on-off crlf
       holdconnect-response = response

       Errors

       338 Invalid directive syntax
       400 Directive not available
       401 Not authorized for directive

       Examples

       C -holdconnect on
       S %ok

       C -holdconnect off
       S %ok

    3.3.6 limit

       Description

       When returning a query result, the server should limit the number of
       objects returned to the client. The "-limit" directive changes this
       limit.  The default and maximum limit is server-dependent. The client
       can get the current limit by using the "-status" directive (see
       Section 3.3.13).

       ABNF

       limit-dir = "-limit" space 1*digit crlf
       limit-response = response

       Errors

       331 Invalid limit
       338 Invalid directive syntax
       400 Directive not available
       401 Not authorized for directive

       Examples

       C -limit 100
       S %ok

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    3.3.7 notify

       Description

       The "-notify" directive performs several functions.

          * If the server returns a referral that results in an error, the
            client can report the bad referral to the server using the
            "badref" option.
          * When the client follows referrals and goes through the same
            referral twice, that referral is a recursive referral and causes
            a referral loop. The client can report the recursive referral to
            the server using the "recurref" option.
          * When the data in an authority area changes, a master server can
            use the "update" option to notify its slave servers to update
            the data.
          * The "inssec" option allows an RWhois server to register itself
            as a slave server for an authority area with a master server.
            The master server may reject the request on the basis of its
            registration policy.
          * The "delsec" option allows a slave server to cancel its
            registration with the master server.

       ABNF

       notify-dir = "-notify" space "badref" space referral-query crlf
               / "-notify" space "recurref" space referral-query crlf
          / "-notify" space "update" space host-port ":" authority-area crlf
               / "-notify" space "inssec" space host-port ":"
                 authority-area crlf
               / "-notify" space "delsec" space host-port ":"
                 authority-area crlf
       referral-query = referral-url space [class-name space] query
       notify-response = response

       See Section 3.4 for the definitions of referral-url and query.

       Errors

       338 Invalid directive syntax
       340 Invalid authority area
       342 Invalid host/port
       400 Directive not available
       401 Not authorized for directive

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       Examples

       # The client reports a bad referral to rwhois.foobar.com to the
       # server.
       C -notify badref rwhois://rwhois.foobar.com:4321/auth-area=foobar.com
         domain foobar.com
       S %ok

       # The client reports a recursive referral to rwhois.foobar.com to the
       # server.
       C -notify recurref rwhois://rwhois.foobar.com:4321/auth-area=
         foobar.com contact Last-Name="Beeblebrox"
       S %ok

       # The master server for the foobar.com authority area notifies its
       # slave servers to update the data.
       C -notify update master.foobar.com:4321:foobar.com
       S %ok

       # The server rwhois2.foobar.com registers as a slave server for the
       # foobar.com authority area.
       C -notify inssec rwhois2.foobar.com:4321:foobar.com
       S %ok

       # The server rwhois2.foobar.com cancels its registration as a slave
       # server for the foobar.com authority area.
       C -notify delsec rwhois2.foobar.com:4321:foobar.com
       S %ok

    3.3.8 quit

       Description

       The "-quit" directive can be used by the client to close the
       connection.  Before the server closes the connection, it must respond
       with "%ok".

       ABNF

       quit-dir = "-quit" crlf
       quit-response = response

       Errors

       No errors.

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       Examples

       C -quit
       S %ok

    3.3.9 register

       Description

       The "-register" directive can be used by the client to add, modify,
       or delete objects in the server's database. The client must wait to
       send the registration data until the "%ok" response is received from
       the server.  This directive has the following options.

          * The "add" option indicates that the object being sent should be
            added to the server's database.
          * The "mod" option indicates that the object being sent is a
            modification of an object that already resides on the server's
            database. During a modify operation, the "_NEW_" tag is used to
            delineate the end of the original (unmodified) object and the
            beginning of the replacement object. That is, the identifying
            characteristics of the original object are sent first, then the
            "_NEW_" separator is sent, and then the entire replacement
            object is sent.
          The "del" option indicates that the object being sent should be
          deleted from the server's database.

       After a register operation (add, modify, or delete an object) in an
       authority area, the server should update the "Serial-Number" variable
       in the SOA information for the authority area. This is useful for
       data replication because a slave server checks the "Serial-Number"
       variable to detect a data change at the master server (see Section
       3.6.2).

       ABNF

       register-dir = register-on space "add" space maintainer-id crlf
                      register-add register-off
               / register-on space "mod" space maintainer-id crlf
                 register-mod register-off
               / register-on space "del" space maintainer-id crlf
                 register-del register-off
       register-on = "-register" space "on"
       register-off = "-register" space "off" crlf
       register-add = 1*(register-line crlf)
       register-mod = 1*(register-line crlf) "_NEW_" crlf
                      1*(register-line crlf)
       register-del = 1*(register-line crlf)

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       maintainer-id = email
       register-line = attribute-name ":" attribute-value
       register-on-response = response
       register-off-response = "%register" space "ID" ":" object-id crlf
                               response
               / "%register" space "Updated" ":" time-stamp crlf response
               / response

          * The server must return the register-on-response for the
            "-register on" directive and the register-off-response for the
            "-register off" directive.
          * The maintainer-id identifies, for maintenance purposes, the
            sender of registration information. The server should not use it
            to authenticate the sender.
          * For the "add" option, the client must send all the required
            attributes for the object, including the Class-Name and Auth-
            Area attributes.  However, the client must not send the ID and
            Updated attributes. These attributes are assigned by the server
            and returned in the response.
          * For the "mod" option, the client must send the identifying
            information for the object to be modified, followed by the
            "_NEW_" separator and the entire replacement object. The
            identifying information must contain the ID and Updated
            attributes; it may contain other attributes, but the server may
            not check them. The ID, Auth-Area, and Class-Name attributes
            must match in both the original object data and the replacement
            object. The original object data is sent before the replacement
            object to enable the server to lock the record in the database.
          * For the "del" option, the client must send the identifying
            information for the object to be deleted. The identifying
            information must contain the ID and Updated attributes; it may
            contain other attributes, but the server may not check them.

       Errors

       120 Registration deferred
       320 Invalid attribute
       321 Invalid attribute syntax
       322 Required attribute missing
       323 Object reference not found
       324 Primary key not unique
       325 Failed to update outdated object
       336 Object not found
       338 Invalid directive syntax
       340 Invalid authority area
       341 Invalid class
       400 Directive not available
       401 Not authorized for directive

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       Examples

       # Add an object.
       C -register on add joe@netsol.com
       S %ok
       C Class-Name:contact
       C Auth-Area:a.com
       C First-Name:Scott
       C Last-Name:Williamson
       C Name:Williamson, Scott
       C Email:scottw@a.com
       C -register off
       S %register ID:23456789.a.com
       S %register Updated:19961205224403000
       S %ok

       # Modify an object.
       C -register on mod joe@netsol.com
       S %ok
       C ID:23456789.a.com
       C Updated:19961205124403000
       C _NEW_
       C Class-Name:contact
       C Auth-Area:a.com
       C ID:23456789.a.com
       C First-Name:Scott
       C Last-Name:Williamson
       C Name:Williamson, Scott
       C Email:sw@a.com
       C -register off
       S %ok

       # Delete an object.
       C -register on del joe@netsol.com
       S %ok
       C ID:23456789.a.com
       C Updated:19961205224403000
       C -register off
       S %ok

    3.3.10 schema

       Description

       The "-schema" directive can be used by the client to get the
       attribute definitions of one or more classes in an authority area. If
       the client specifies class names, the server must return the
       attribute definitions of the specified classes. Otherwise, the server

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    RFC 2167                    RWhois Protocol                    June 1997

       must return the attribute definitions of all the classes in the
       authority area. Every schema record must end with an empty "%schema"
       line.

       ABNF

       schema-dir = "-schema" space authority-area *(space class-name) crlf
       schema-response = *schema-record response
       schema-record = *schema-line "%schema" crlf
       schema-line = "%schema" space class-name ":" attribute-name ":"
                     attribute-value crlf

       Errors

       338 Invalid directive syntax
       340 Invalid authority area
       341 Invalid class
       400 Directive not available
       401 Not authorized for directive

       Examples

       C -schema map
       S %schema map:attribute:Class-Name
       S %schema map:description:Type of the object
       S %schema map:type:TEXT
       S %schema map:format:re:[a-zA-Z0-9-]+
       S %schema map:indexed:OFF
       S %schema map:required:ON
       S %schema map:multi-line:OFF
       S %schema map:repeatable:OFF
       S %schema map:primary:OFF
       S %schema map:hierarchical:OFF
       S %schema map:private:OFF
       S %schema
       S %schema map:attribute:ID
       S %schema map:description:Globally unique object identifier
       S %schema map:type:TEXT
       S %schema map:format:re:[0-9]+.[a-zA-Z0-9.-]+

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       S %schema map:indexed:ON
       S %schema map:required:ON
       S %schema map:multi-line:OFF
       S %schema map:repeatable:OFF
       S %schema map:primary:ON
       S %schema map:hierarchical:OFF
       S %schema map:private:OFF
       S %schema
       # This is an abbreviated example, more attributes usually follow.
       S %ok

    3.3.11 security

       Description

       The "-security" directive enables either a client request or a server
       response to be authenticated and/or encrypted. Currently, RWhois uses
       two standard security methods: password and PGP. Password provides
       authentication only, and PGP provides both authentication and
       encryption.  This directive can be used to securely access or update
       any information (meta or data) in an authority area that is protected
       by one or more guardian objects.

       ABNF

       security-dir = "-security" space "on" space direction space
               security-method [space security-data] crlf
               security-payload ["-security" space "off" crlf]
       direction = "request" / "response"
       security-method = "password" / "pgp" / 1*id-char
       security-data = password-data / pgp-data / 1*any-char
       password-data = 1*any-char
       pgp-data = "signed" / "encrypt" [space key-id] / "signed-encrypt"
                  [space key-id]
       security-payload = *(*any-char crlf)
       security-response = response

          * The "password" security-method is available in the "request"
            direction only. For password, the security-data is a cleartext
            password.
          * The "pgp" security-method is available in both the "request" and
            "response" directions. For PGP, the security-data indicates how
            to treat the security-payload: signed, encrypted, or signed and
            encrypted. To encrypt the security-payload in the "response"
            direction, the security-data must include the public key ID with
            which to encrypt it.

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       Errors

       338 Invalid directive syntax
       352 Invalid security method
       353 Authentication failed
       354 Encryption failed
       400 Directive not available
       401 Not authorized for directive

       Examples

       # Authenticate a request using password.
       C -security on request password hello!1
       S %ok

       # Authenticate a PGP signed request.
       C -security on request pgp signed
       S %ok
       C -register on mod joe@netsol.com
       S %ok
       C -----BEGIN PGP MESSAGE-----
       C Version: 2.6.2
       C
       C owHrZJjKzMpgdP9D9crUhdpBYnwHGRnPbmVhmHlV7Hef9je/n7vyzhmE6589/+Dg
       C jPpVm59tNz92vPSmrFB/4ankBRz+xgY+7z9OUYjefGahbWSNwzzxbw6TpWZGerU+
       C uOUg/Cygs33JBdHqjwEc+wyfZPp+N5p2bu+ywoaOu8eLPyn+m2Mt/T9p1UaG68vP
       C Zd2d9EPw+Ywpio7dco6yh3b/v7zmQxJHcWpyaVFmSSUDEHi6WBkZm5iamVtY6iXq
       C JefnKnCFFqQklqSmWBlaWpoZGhmYGhqZmBgYGxgYKHA55yQWF+v6JeamWiXn55Uk
       C JpcocDmWlmToOhalJlpB9cf7uYbHE6kWi/VumUXFJRB9wcn5JUBdPokwgfDMnJzM
       C xNzi/DwFLjQBHQWoatfcxMwcq+JyB6h5AA==
       C =a0sQ
       C -----END PGP MESSAGE-----
       C -register off
       S %ok

       # Encrypt a response using PGP. 52160EC1 is the public key ID with
       # which the response is encrypted.
       C -security on response pgp encrypt 52160EC1
       S %ok
       C -xfer com class=domain attribute=Domain-Name
         attribute=Organization-Name
       S -----BEGIN PGP MESSAGE-----
       S Version: 2.6.2
       S
       S hIwDqWWhK1IWDsEBBACOXssTzD2CbB7Vjj2cNURScpJc2as2TbUDOQiwkT+8qFgG
       S ZyRfktpwNNTawRIcGOk1Kcs84z8a3vvTA/oje9vZexHtzfJwBHFdiIZxPuCEpvgv
       S 2ppK7WqlmHGcQKVBJJHYw7Fq83CUkeGJB9P1M3CQiXeW8h8MwAuhxSgbgt23PKYA
       S AABuhknJrXeh9Owm81+MvyzgLOyM7sjDYmttU9sj/yuOYmAhS9V+34MT/Mwn4wO8

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       S 2BCsJqBHXbwOuYKs02p0se4jyKFtZR8MDPWNm9QyAP+oNMTjsufy6ZRa9PegUC6t
       S HDhXymkiP03mKMMVK1//7X0=
       S =vZ2x
       S -----END PGP MESSAGE-----
       S %ok

    3.3.12 soa

       Description

       The "-soa" directive can be used by the client to retrieve the SOA
       information for one or more authority areas. When no authority area
       name is given, the server must return the SOA information for all the
       authority areas. Every SOA record must end with an empty "%soa" line.

       ABNF

       soa-dir = "-soa" *(space authority-area) crlf
       soa-response = *soa-record response
       soa-record = *soa-line "%soa" crlf
       soa-line = "%soa" space "authority" ":" authority-area crlf
          / "%soa" space "ttl" ":" 1*digit crlf
          / "%soa" space "serial" ":" time-stamp crlf
          / "%soa" space "refresh" ":" 1*digit crlf
          / "%soa" space "increment" ":" 1*digit crlf
          / "%soa" space "retry" ":" 1*digit crlf
          / "%soa" space "tech-contact" ":" email crlf
          / "%soa" space "admin-contact" ":" email crlf
          / "%soa" space "hostmaster" ":" email crlf
          / "%soa" space "primary" ":" host-port crlf
          / "%soa" space attribute-name ":" attribute-value crlf

       The server must return the following SOA information for an authority
       area.

     attribute-name  attribute-value Comments

     authority       authority-area  This is the name of the authority area.

     ttl             1*digit         This is the default time to live for
                                     the data in the authority area.

     serial          time-stamp      This is the serial number of the data
                                     in the authority area; it changes
                                     when the data changes.

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     refresh         1*digit         This is the time interval before a
                                     slave server checks for complete
                                     replication.

     increment       1*digit         This is the time interval before a
                                     slave server checks for incremental
                                     replication.

     retry           1*digit         This is the time interval before a
                                     slave server tries again to connect
                                     to a master server that appears to be
                                     out-of-service.

     tech-contact    email           This is the contact for the operation
                                     of the master server.

     admin-contact   email           This is the contact for the data
                                     integrity at the master server.

     hostmaster      email           This is the contact for sending update
                                     requests at the master server.

     primary         host-port       This is the host name (or IP address)
                                     and port number of the master server.

       Errors

       338 Invalid directive syntax
       340 Invalid authority area
       400 Directive not available
       401 Not authorized for directive

       Examples

       C -soa org
       S %soa authority:org
       S %soa ttl:86400
       S %soa serial:19961119111535000
       S %soa refresh:3600
       S %soa increment:1800
       S %soa retry:180
       S %soa tech-contact:tech@internic.net
       S %soa admin-contact:admin@internic.net
       S %soa hostmaster:hostmaster@internic.net
       S %soa primary:rs.internic.net:4321
       S %soa
       S %ok

    Williamson, et. al.          Informational                     [Page 36]

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    3.3.13 status

       Description

       The "-status" directive can be used by the client to get various
       status flags from the server. The response must include the number of
       objects in all the authority areas, the current display format, the
       server contact information, and the status flags for the state-
       oriented directives:  "-limit", "-holdconnect", and "-forward".

       ABNF

       status-dir = "-status" crlf
       status-response = *status-line response
       status-line = "%status" space "limit" ":" 1*digit crlf
          / "%status" space "holdconnect" ":" on-off crlf
          / "%status" space "forward" ":" on-off crlf
          / "%status" space "objects" ":" 1*digit crlf
          / "%status" space "display" ":" 1*any-char crlf
          / "%status" space "contact" ":" email crlf
          / "%status" space attribute-name ":" attribute-value crlf

       Errors

       338 Invalid directive syntax
       400 Directive not available
       401 Not authorized for directive

       Examples

       C -status
       S %status limit:20
       S %status holdconnect:OFF
       S %status forward:OFF
       S %status objects:12345
       S %status display:dump
       S %status contact:joe@rwhois.net
       S %ok

    3.3.14 xfer

       Description

       The "-xfer" directive can be used by the client (generally, a slave
       server) to transfer the data in an authority area. The client can
       control the amount of data transferred using one of the following
       options.

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          * serial-number: The client can transfer all the objects that have
            been added, modified or deleted since a certain time, specifying
            the serial-number that indicates that time. This option is used
            for incremental replication.
          * class: The client can limit the data transfer to one or more
            classes, using the "class=<class-name>" option. The server must
            return data for only the specified classes. If no class name is
            specified, the server must return data for all the classes.
          * attribute: The client can limit the data transfer to one or more
            attributes of a class, using the "attribute=<attribute-name>"
            option in combination with the "class=<class-name>" option. The
            server must return data for only the specified attributes of the
            class. The client can specify multiple "class=" and "attribute="
            pairs.

       ABNF

       xfer-dir = "-xfer" space authority-area *attribute-def
               [space serial-number] crlf
       attribute-def = [space "class=" class-name] *(space "attribute="
                       attribute-name)
       serial-number = time-stamp
       xfer-response = *xfer-record response
       xfer-record = *xfer-line "%xfer" crlf
       xfer-line = "%xfer" space class-name ":" attribute-name ":"
                   attribute-value crlf

       Errors

       332 Nothing to transfer
       333 Not master for authority area
       338 Invalid directive syntax
       340 Invalid authority area
       341 Invalid class
       342 Invalid attribute
       400 Directive not available
       401 Not authorized for directive

    Williamson, et. al.          Informational                     [Page 38]

    RFC 2167                    RWhois Protocol                    June 1997

       Examples

       C -xfer com class=domain attribute=Domain-Name
         attribute=Organization-Name
       S %xfer domain:Domain-Name:acme.com
       S %xfer domain:Organization-Name:Acme Inc.
       S %xfer
       S %xfer domain:Domain-Name:vogon.com
       S %xfer domain:Organization-Name:Vogon Heavy Industries
       S %xfer
       S %ok

    3.3.15 X

       Description

       The "-X" directive is used to specify an additional, non-standard
       directive. It can be implemented by executing an external program, by
       internal functions, or by other means. It may interact with the
       client or simply produce output like one of the standard directives.

       ABNF

       x-dir = "-X-" x-directive [space x-arguments] crlf *x-line
       x-directive = 1*id-char
       x-arguments = *any-char
       x-response = *(*any-char crlf) response
       x-line = *any-char crlf

       Errors

       338 Invalid directive syntax
       400 Directive not available
       401 Not authorized for directive

       Examples

       The following example uses an implementation that executes an
       external program, the UNIX "date" command. The server runs the "date"
       command and returns its output to the client.

       C -X-date
       S Mon Jan 6 13:21:20 EST 1997
       S %ok

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    RFC 2167                    RWhois Protocol                    June 1997

    3.4 Query

       Description

       The query allows the client to retrieve objects from the server's
       database.  The server must support the following types of queries.

          * Unrestricted query: It is a single word or a quoted string. The
            server must return all the matching objects where one or more
            attributes match the query, regardless of the class.
          * Class-restricted query: It is a class name specified in front
            of the unrestricted query. The server must return all the
            matching objects where one or more attributes of the specified
            class match the query.
          * Attribute-restricted query: It is of the
            "<attribute-name>=<search-string>" form. The server must return
            all the matching objects where the specified attribute matches
            the query.

       The server may implement the following types of queries.

          * Boolean operator query: It consists of simpler queries combined
            using the "and" and "or" operators.
          * Wild card query: It consists of an asterisk ("*") in the front
            and/or at the end of the search string. The server may support
            partial matching using the asterisk.

       In response to the query, the server will return the objects that
       match the query. If the server does not support complex queries,
       with, for example, wild cards or boolean operators, the server may
       return the "351 Query too complex" error. When the number of objects
       found exceeds the limit (set by the "-limit" directive), the server
       should return the objects, followed by the "330 Exceeded maximum
       objects limit" error.

       The default object output format is the dump format that uses the
       "<class-name>:<attribute-name>;<type character>:<attribute-value>"
       form.  The type character is optional and identifies the type of the
       attribute value. The type character is a shorthand for the Type field
       of the attribute definition (see Section 2.3.1). The type characters
       are defined as follows.

    Williamson, et. al.          Informational                     [Page 40]

    RFC 2167                    RWhois Protocol                    June 1997

        Type          Attribute
        character     Type

        T             TEXT

        I             ID

        S             SEE-ALSO

       When no type character is given, the client should assume the "T"
       type character. The server must provide the type character when the
       attribute type is ID or SEE-ALSO. The purpose of the type character
       is to aid the client in displaying the data. For example, when an
       attribute value is an ID, the client may indicate to the end-user
       that it is possible to retrieve the object indicated by the ID.

       The server may return one or more referrals in the "%referral
       rwhois://<host-name>:<port-number>/auth-area=<authority area>" form.
       The client can distinguish multiple referrals by comparing their
       authority areas; if all the referrals refer to the same authority
       area, the client should follow only one of them. Otherwise, the
       client should follow all of them. To follow a referral, the client
       must connect to the specified host name and port number, and issue
       the same query.

       ABNF

       rwhois-query = [class-name space] query crlf
       query = query-string / attribute-query / query bin-boolean query
       query-char = <any-char, except """, space, tab>
       quoted-query-char = query-char / space / tab / "
       query-string = ["*"] 1*query-char ["*"] / """ ["*"]
               1*quoted-query-char ["*"] """
       attribute-query = attribute-name "=" query-string
       bin-boolean = "and" / "or"

       rwhois-query-result = *(query-record / referral-record) response
       query-record = 1*query-line crlf
       query-line = class-name ":" attribute-name [";" type-char] ":"
               attribute-value crlf
       type-char = "T" / "I" / "S"
       referral-record = 1*(referral-line crlf)
       referral-line = "%referral" space referral-url
       referral-url = "rwhois" ":" "//" host-port "/" "auth-area="
                      authority-area

    Williamson, et. al.          Informational                     [Page 41]

    RFC 2167                    RWhois Protocol                    June 1997

       Errors

       130 Object not authoritative
       230 No objects found
       330 Exceeded maximum objects limit
       340 Invalid authority area
       341 Invalid class
       342 Invalid attribute
       350 Invalid query syntax
       351 Query too complex

       Examples

       This example illustrates a query, where no objects are found.

       C vogon
       S %error 230 No objects found

       This example illustrates a query, where two different objects are
       returned.

       C ibm
       S domain:ID:IBMLIFEPRO-DOM.com
       S domain:Auth-Area:com
       S domain:Domain-Name:IBMLIFEPRO.COM
       S domain:Org-Name:IBM
       S domain:Server;I:NS12345-HST.NET
       S domain:Server;I:NS12345-HST.NET
       S domain:Admin-Contact;I:TW1234.COM
       S domain:Tech-Contact;I:BN123.NET
       S domain:Updated:19961120123455000
       S domain:Updated-By:autoreg@internic.net
       S domain:Class-Name:domain
       S
       S network:ID:NET-IBMNET-3.0.0.0/0
       S network:Auth-Area:0.0.0.0/0
       S network:Network-Name:IBMNET-3
       S network:IP-Network:123.45.67.0/24
       S network:Org-Name:IBM
       S network:Street-Address:1234 Maneck Avenue
       S network:City:Black Plains
       S network:State:NY
       S network:Postal-Code:12345
       S network:Country-Code:US
       S network:Tech-Contact;I:MG305.COM
       S network:Updated:19931120123455000
       S network:Updated-By:joeblo@nic.ddn.mil
       S network:Class-Name:network

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       S
       S %ok

       This example illustrates a query with a class restrictor, where the
       number of objects found exceeds the limit set by the "-limit"
       directive.

       C -limit 1
       S %ok
       C domain ibm
       S domain:ID:IBMLIFEPRO-DOM.com
       S domain:Auth-Area:com
       S domain:Domain-Name:IBMLIFEPRO.COM
       S domain:Org-Name:IBM
       S domain:Server;I:NS12345-HST.NET
       S domain:Server;I:NS12345-HST.NET
       S domain:Admin-Contact;I:TW1234.COM
       S domain:Tech-Contact;I:BN123.NET
       S domain:Updated:19961120123455000
       S domain:Updated-By:erice@internic.net
       S domain:Class-Name:domain
       S
       S %error 330 Exceeded maximum objects limit

       This is an example of attribute matching.

       C domain Domain-Name=konabo.com
       S domain:ID:12345678.com
       S domain:Auth-Area:com
       S domain:Domain-Name:konabo.com
       S domain:Org-Name:ACME
       S domain:Server;I:12345670.com
       S domain:Server;I:12345671.com
       S domain:Admin-Contact;I:12345660.com
       S domain:Tech-Contact;I:12345665.com
       S domain:Updated:19961120123455000
       S domain:Updated-By:joeblo@internic.net
       S domain:Class-Name:domain
       S
       S %ok

       This example illustrates a link referral.

       C domain a.b.rwhois.net
       # The server returns a link referral to a server serving the
       # b.rwhois.net authority area.
       S %referral rwhois://master.b.rwhois.net:4321/auth-area=b.rwhois.net
       S %ok

    Williamson, et. al.          Informational                     [Page 43]

    RFC 2167                    RWhois Protocol                    June 1997

       This example illustrates a punt referral.

       C domain internic.net
       # The server returns a punt referral to a server serving the root
       # authority area.
       S %referral rwhois://rs.internic.net:4321/auth-area=.
       S %ok

       This example illustrates multiple referrals that refer to the same
       authority area. The client should follow only one of them.

       C domain a.b.rwhois.net
       # The server returns link referrals to two RWhois servers serving the
       # b.rwhois.net authority area.
       S %referral rwhois://master.b.rwhois.net:4321/auth-area=b.rwhois.net
       S %referral rwhois://slave.b.rwhois.net:4321/auth-area=b.rwhois.net
       S %ok

       This example illustrates multiple referrals that refer to different
       authority areas. The client should follow all of them.

       C contact Last-Name="Beeblebrox"
       # The server returns a link referral to a server serving the
       # b.rwhois.net authority area.
       S %referral rwhois://master.b.rwhois.net:4321/auth-area=b.rwhois.net
       # The server also returns a punt referral to a server serving the
       # net authority area since the query matched an entry in the
       # non-hierarchical index received from it.
       S %referral rwhois://rs.internic.net:4321/auth-area=net
       S %ok

    Williamson, et. al.          Informational                     [Page 44]

    RFC 2167                    RWhois Protocol                    June 1997

       This is an example of a boolean operator and wildcard matching.

       C ibm and jubliana*
       S host:ID:JUBLIANA-HST.root
       S host:Auth-Area:.
       S host:Host-Name:JUBLIANA.TRL.IBM.CO.JP
       S host:IP-Address:123.156.220.68
       S host:Org-Name:IBM
       S host:Street-Address:1234 Maneck Avenue
       S host:City:Black Plains
       S host:State:NY
       S host:Postal-Code:12345
       S host:Country-Code:US
       S host:Updated:19961120123455000
       S host:Updated-By:joeblo@nic.ddn.mil
       S host:Class-Name:host
       S
       S %ok

    3.5 Connection Model

       An RWhois client can connect to an RWhois server using one of the
       following transport protocols.

    3.5.1 Transmission Control Protocol (TCP)

       TCP provides a reliable stream transport service between a client and
       a server. In RWhois, TCP is the default transport protocol because,
       during a particular session, a client can send more than one query
       and a server can reliably return a large amount of data for each of
       those queries. By default, a TCP RWhois server should run on the
       standard, Internet Assigned Number Authority (IANA)-assigned port
       4321. However, if port 4321 is not available, it may run on an
       available port in the non-reserved range (1024 - 65535).

    3.5.2 User Datagram Protocol (UDP)

       UDP provides an unreliable connectionless transport service between a
       client and a server. In RWhois, UDP may be used as the transport
       protocol if a client wants to quickly send only one query, without
       incurring the overhead of establishing a TCP connection with a
       server. By default, a UDP RWhois server should run on the standard,
       IANA-assigned port 4321. However, if port 4321 is not available, it
       may run on an available port in the non-reserved range (1024 -
       65535). A separate document will describe the use of UDP as the
       transport protocol in RWhois.

    Williamson, et. al.          Informational                     [Page 45]

    RFC 2167                    RWhois Protocol                    June 1997

    3.6 Data Replication

       This section discusses when and how a slave server should replicate
       data.  Further, it describes the server registration and location
       mechanisms.

    3.6.1 When to Replicate Data

       The time when a slave server may replicate data for an authority area
       is determined by the SOA variables for that authority area. The
       possible times are the following.

          * When the "Refresh-Interval" expires, a slave server may
            completely replicate data.
          * When the "Increment-Interval" expires, a slave server may
            incrementally replicate data.
          * A slave server fails to connect to its master server to
            replicate data. When the "Retry-Interval" expires, it tries
            again to replicate data.
          * When the data in an authority area is changed and its "Serial-
            Number" updated, a master server may notify its slave servers to
            immediately update the data. To notify about the data change,
            the master server should send the "-notify update <host-
            name>:<port-number>:<authority-area>" directive to its slave
            servers.

    3.6.2 How to Replicate Data

       To replicate data, a slave server sends a series of directives to its
       master server and checks each response before sending the next
       directive.  The following sections describe the protocols for
       complete and incremental replication.

       Complete Replication

       The protocol between a master server and a slave server to completely
       replicate data for an authority area is as follows.

         1. The slave server should connect to the master server. If there
            is a connection error, the slave server should log an error and
            exit.

         2. The slave server should send the "-soa <authority-area>"
            directive to the master server and parse the SOA variables from
            the response. Let the "Serial-Number" variable in this response
            be called the "old-serial-number".

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         3. The slave server should send the "-class <authority-area>"
            directive to the master server and parse the versions of all the
            classes from the response.
         4. The slave server should send the "-schema <authority-area>"
            directive to the master server and parse the definitions of all
            the classes from the response.
         5. The slave server should send the "-xfer <authority-area>"
            directive to the master server and parse the data objects from
            the response. The master server should return all the data
            objects, excluding the deleted ones, in the authority area. The
            slave server should index these data objects.
         6. When the "Refresh-Interval" expires, the slave server should
            to the master server. If there is a connection error, the slave
            server should try again after the "Retry-Interval".
         7. The slave server should send the "-soa <authority-area>"
            directive to the master server and parse the SOA variables from
            the response. Let the "Serial-Number" variable in this response
            be called the "new-serial-number". If the "new-serial-number" is
            not greater than the "old-serial-number", go back to step 6.
            Otherwise, it indicates a data change at the master server.
         8. The slave server should send the "-class <authority-area>"
            directive to the master server and parse the versions of all the
            classes from the response. If the version of any of the classes
            has changed, the slave server should send the "-schema
            <authority-area>" directive to the master server and parse the
            definitions of all the classes from the response.
         9. The slave server should send the "-xfer <authority-area>"
            directive the master server and parse the data objects from the
            response. The master server should return all the data objects,
            excluding the deleted ones, in the authority area. The slave
            server should index these data objects and seamlessly replace
            the old index with the new one. Further, it should assign the
            "new-serial-number" to the "old-serial-number".
         10. Go back to step 6.

       Note that the "-class", "-schema", and "-xfer" directives change when
       a slave server replicates data for only a subset of the schema for an
       authority area.

       In the following example, a slave server completely replicates data
       for all the classes in an authority area. The notation in the example
       uses a prefix to indicate from where the information is coming. An
       "M" indicates that the master server sends the data to the slave
       server. An "S" indicates that the slave server sends the data to the
       master server. The line is a comment when "#" is used. The space
       after the prefix is not part of the data. The example authority area
       is "rwhois.net".

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       # The slave server connects to the master server.
       M %rwhois V-1.5:00ffff:00 master.rwhois.net
       S -soa rwhois.net
       M ...
       M %soa serial:19970103102258000
       M %soa refresh:3600
       M ...
       S -class rwhois.net
       # The master server returns the versions of all the classes in the
       # rwhois.net authority area.
       S -schema rwhois.net
       # The master server returns the definitions of all the classes in the
       # rwhois.net authority area.
       S -xfer rwhois.net
       # The master server returns all the data objects, excluding the
       # deleted ones, in the rwhois.net authority area. The slave server
       # indexes these data objects.
       # The refresh interval of 3600 seconds expires.
       S -soa rwhois.net
       M ...
       M %soa serial:19970103103258000
       M %soa refresh:3600
       M ...
       # The new serial number 19970103103258000 is greater than the old
       # serial number 19970103102258000. It indicates a data change at the
       # master server.
       S -class rwhois.net
       # The master server returns the versions of all the classes in the
       # rwhois.net authority area. If the version of any of the classes has
       # changed, the slave server logs an error and closes the connection.
       S -xfer rwhois.net
       # The master server returns all the data objects, excluding the
       # deleted ones, in the rwhois.net authority area. The slave server
       # indexes these data objects and seamlessly replaces the old index.
       # The refresh interval of 3600 seconds expires.
       S ...

       Incremental Replication

       The protocol between a master server and a slave server to
       incrementally replicate data for an authority area is as follows.

         1. The slave server should connect to the master server. If there
            is a connection error, the slave server should log an error and
            exit.

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         2. The slave server should send the "-soa <authority-area>"
            directive to the master server and parse the SOA variables from
            the response. Let the "Serial-Number" variable in this response
            be called the "old-serial-number".
         3. The slave server should send the "-class <authority-area>"
            directive to the master server and parse the versions of all the
            classes from the response.
         4. The slave server should send the "-schema <authority-area>"
            directive to the master server and parse the definitions of all
            the classes from the response.
         5. The slave server should send the "-xfer <authority-area>"
            directive to the master server and parse the data objects from
            the response. The master server should return all the data
            objects, excluding the deleted ones, in the authority area. The
            slave server should index these data objects.
         6. When the "Increment-Interval" expires, the slave server should
            connect to the master server. If there is a connection error,
            the slave server should try again after the "Retry-Interval".
         7. The slave server should send the "-soa <authority-area>"
            directive to the master server and parse the SOA variables from
            the response. Let the "Serial-Number" variable in this response
            be called the "new-serial-number". If the "new-serial-number" is
            not greater than the "old-serial-number", go back to step 6.
            Otherwise, it indicates a data change at the master server.
         8. The slave server should send the "-class <authority-area>"
            directive to the master server and parse the versions of all the
            classes from the response. If the version of any of the classes
            has changed, the slave server should send the "-schema
            <authority-area>" directive to the master server and parse the
            definitions of all the classes from the response. The slave
            server should then send the "-xfer <authority-area>" directive
            to the master server and parse the data objects from the
            response. The master server should return all the data objects,
            excluding the deleted ones, in the authority area. The slave
            server should index these data objects and seamlessly replace
            the old index with the new one. Further, it should assign the
            "new-serial-number" to the "old-serial-number". If the version
            of any of the classes has changed, go back to step 6.
         9. The slave server should send the "-xfer <authority-area>
            <old-serial-number>" directive to the master server and parse
            the data objects from the response. The master server should
            return all the data objects in the authority area that have been
            inserted, updated, or deleted since the "old-serial-number". The
            slave server should index all the data again after purging stale
            data objects and seamlessly replace the old index with the new
            one. Further, it should assign the "new-serial-number" to the
            "old-serial-number".
         10. Go back to step 6.

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       Note that the "-class", "-schema", and "-xfer" directives change when
       a slave server replicates data for only a subset of the schema for an
       authority area.

       In the following example, a slave server incrementally replicates
       data for all the classes in an authority area. The notation in the
       example uses a prefix to indicate from where the information is
       coming. An "M" indicates that the master server sends the data to the
       slave server. An "S" indicates the slave server sends the data to the
       master server. The line is a comment when "#" is used. The space
       after the prefix is not part of the data. The example authority area
       is "rwhois.net".

       # The slave server connects to the master server.
       M %rwhois V-1.5:00ffff:00 master.rwhois.net
       S -soa rwhois.net
       M ...
       M %soa serial:19970103102258000
       M %soa increment:1800
       M ...
       S -class rwhois.net
       # The master server returns the versions of all the classes in the
       # rwhois.net authority area.
       S -schema rwhois.net
       # The master server returns the definitions of all the classes in the
       # rwhois.net authority area.
       S -xfer rwhois.net
       # The master server returns all the data objects, excluding the
       # deleted ones, in the rwhois.net authority area. The slave server
       # indexes these data objects.
       # The increment interval of 1800 seconds expires.
       S -soa rwhois.net
       M ...
       M %soa serial:19970103103258000
       M %soa increment:1800
       M ...
       # The new serial number 19970103103258000 is greater than the old
       # serial number 19970103102258000. It indicates a data change at
       # the master server.
       S -class rwhois.net
       # The master server returns the versions of all the classes in the
       # rwhois.net authority area. If the version of any of the classes has
       # changed, the slave server logs an error and closes the connection.
       S -xfer rwhois.net 19970103102258000

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       # The master server returns all the data objects in the rwhois.net
       # authority area that have been inserted, updated, or deleted since
       # 19970103102258000. The slave server indexes all the data again
       # after purging stale data objects and seamlessly replaces the old
       # index. The increment interval of 1800 seconds expires.
       S ...

    3.6.3 Server Registration

       This section discusses how an RWhois server can register itself or
       cancel its registration as a slave server for an authority area with
       a master server.

       The initial list of slave servers for an authority area should be
       manually configured at the master server. To register itself as a
       slave server, the server should send the "-notify inssec <host-
       name>:<port-number>:<authority-area>" directive to the master server.
       The master server may reject the request on the basis of its
       registration policy. To cancel its registration as a slave server,
       the server should send the "-notify delsec <host-name>:<port-
       number>:<authority-area>" directive to the master server. Note that
       the "host-name" and "port-number" in the above directives correspond
       to the requesting server.

    3.6.4 Server Location

       To resolve a query in a particular authority area, an RWhois client
       may need to first locate the master and slave servers for that
       authority area.  The different server location mechanisms are as
       follows.

       Referrals

       An RWhois client should know about at least one RWhois server. It
       should send the "referral <authority-area>" query to that server. The
       query may be routed up or down the RWhois tree before getting
       resolved. If the query does get resolved, the result should be a
       referral object for that authority area. The client should parse the
       "Referral" attributes from the result to obtain a list of servers
       serving that authority area.

       The client should then send the "-soa <authority-area>" directive to
       one of the above servers and parse the "Primary-Server" variable from
       the response. The value of this variable is the master server. Then,
       the remaining servers in the list are the slave servers.

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       SRV RRs

       The Server Resource Record (SRV RR), defined for DNS, can be used to
       locate the master and slave servers for an authority area. An SRV RR
       specifies the location of a network service in an organization's DNS.
       It is defined in [RFC 2052] as follows.

       Service.Proto.Name TTL Class SRV Priority Weight Port Target

       Since an authority area identifier is generally a domain name or an
       IP address, the RWhois SRV RRs can be added to the DNS file for that
       domain or IP address. For example, the RWhois SRV RRs for the
       "rwhois.net" authority area could be:

       rwhois.tcp.rwhois.net. 86400 IN SRV 10 0 4321 master.rwhois.net.
                                       SRV 20 0 4322 slave.rwhois.net.

       where the "master.rwhois.net" server has a higher priority than the
       "slave.rwhois.net" server. The client must try to connect to the
       server with a higher (lower-numbered) priority.

    4. Security Considerations

       RWhois provides security using the guardian class (see Section
       2.3.6). Any information (meta or data) in an authority area can be
       guarded by containing pointers to one or more guardian objects; that
       is, it can be securely updated and accessed. Currently, there are two
       standard security methods: password and PGP (see Section 3.3.11).
       Password provides authentication only, and PGP provides both
       authentication and encryption.  PGP is the recommended security
       method in RWhois.

       The following sections discuss how to securely update and access the
       data in an authority area.

    4.1 Data Update

       This involves the ability to securely add, modify, or delete some
       information (meta or data) in an authority area. An authority area,
       on the whole, can be guarded by linking guardians to its SOA and
       schema information. Only these guardians should be allowed to add
       objects to the authority area and modify its SOA and schema
       information. In addition, they can also modify or delete existing
       objects in the authority area. However, the function of modifying or
       deleting existing objects can be delegated to other guardians by
       linking them to objects on a per-object basis.

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    4.2 Access Control

       There are two access control issues; the first is the ability to
       securely transfer data between the slave and master servers. To
       transfer data for an authority area, a slave server can authenticate
       itself by satisfying one of the guardians linked to the SOA
       information of the authority area at the master server. In addition,
       the master server may encrypt the transferred data.

       The second issue is the ability to make public only a subset of the
       data in an authority area. If all the objects of a particular class
       need to be private, the Private attribute of the class should be set
       to true. If only some attributes of all the objects of a particular
       class need to be private, the Private attribute property of each of
       those attributes should be set to true. The guardians of such objects
       must be able to view them completely.

    5. Acknowledgments

       The authors would like to acknowledge the following individuals.

       Stan Borinski
       C. Ming Lu
       Leslie Meador
       Michael Mealling
       Greg Pierce
       Amar Rao

    6. References

       [CIP] Allen, J., "The Common Indexing Protocol (CIP)", Bunyip
       Information Systems, November 1996, Work in Progress.

       [Guardian] Singh, J., M. Kosters, "The InterNIC Guardian Object",
       ftp://rs.internic.net/policy/internic/internic-gen-1.txt, Network
       Solutions, February 1996.

       [RFC 821] Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC
       821, ISI, August 1982.

       [RFC 822] Crocker, D, "Standards for the Format of ARPA Internet Text
       Messages", STD 11, RFC 822, University of Delaware, August 1982.

       [RFC 954] Harrenstien, K., Stahl, M., Feinler, E., "NICNAME/WHOIS",
       RFC 954, SRI, October 1985.

       [RFC 1034] Mockapetris, P. V., "Domain names - concepts and
       facilities", STD 13, RFC 1034, November 1987.

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    RFC 2167                    RWhois Protocol                    June 1997

       [RFC 1714] Williamson, S., Kosters, M., "Referral Whois Protocol",
       RFC 1714, Network Solutions, November 1994.

       [RFC 1738] T. Berners-Lee, L. Masinter, M. McCahill, "Uniform
       Resource Locators (URL)", RFC 1738, CERN, Xerox Corporation,
       University of Minnesota, December 1994.

       [RFC 1991] Atkins, D.,  W. Stallings, P. Zimmermann, "PGP Message
       Exchange Formats", RFC 1991, MIT, Comp-Comm Consulting, Boulder
       Software Engineering, August 1996.

       [RFC 2052] Gulbrandsen, A., P. Vixie, "A DNS RR for specifying the
       location of services (DNS SRV)", RFC 2052, Troll Technologies, Vixie
       Enterprises, October 1996.

       [X.500] "The Directory: Overview of Concepts, Models and Service",
       CCITT Recommendation X.500, 1988.

    Authors' Addresses

       Scott Williamson (scottw@rwhois.net)
       Mark Kosters (markk@internic.net)
       David Blacka (davidb@rwhois.net)
       Jasdip Singh (jasdips@rwhois.net)
       Koert Zeilstra (kzeil@rwhois.net)

       Postal Address:
       505 Huntmar Park Drive
       Herndon, VA 22070-5100
       Telephone: 703-742-0400

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       Appendix A: Glossary Of Terms

       ABNF: Augmented Backus-Naur Form. Refined version of BNF, defined in
       [RFC 822]. See BNF.

       Attribute: A named field and the smallest typed unit in a database
       schema.  See Database Schema.

       Authority Area: An autonomous part of an RWhois tree. It is
       associated and named after a particular piece of a hierarchy and is
       able to state authoritatively whether or not an instance of
       hierarchical data is present within the RWhois tree. See RWhois Tree.

       Banner: A line sent by a server indicating which protocol versions it
       supports and which directives are implemented. This line is issued by
       the server after a connection is opened and as a response to the "-
       rwhois" directive. See Directive and Response.

       Base Class: A class from which all defined classes in a database
       schema inherit attributes. See Attribute, Class, and Database Schema.

       BNF: Backus-Naur Form. Language to precisely define the syntax of
       protocols and computer languages.

       Class: A collection of attributes. See Attribute.

       Complete Replication: The process of replicating all of the data for
       an authority area. See Replication.

       Database Schema: A collection of all the classes forming an RWhois
       database. See Class.

       Directive: A command that a client sends to a server to set a control
       parameter for the session, get the meta-information (class
       definitions and SOA information) about an authority area, or get the
       data in an authority area. See Class and SOA.

       Guardian Class: A standard class that contains security information.
       An object is guarded by containing a pointer to a guardian object.
       See Class and Object.

       Incremental Replication: The process of replicating the data that has
       changed since the last replication for an authority area. See
       Replication.

       Info: The miscellaneous information that a server sends to a client.

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       Lexically Hierarchical Label: A text string whose position in a
       hierarchy is encoded in the string itself.

       Link Referral: A pointer to another server that is further down an
       RWhois tree. It is used to route a query down the tree. See Referral
       and RWhois Tree.

       Master Server: A server where the data is registered for an authority
       area.  It answers authoritatively to queries in the authority area.
       It is also called a primary server. See Authority Area.

       Namespace: A particular naming system defined by a set of rules
       describing the format of a name. Alternately, all of the names
       satisfying the rules.

       Object: An instance of a class. It is data with a type of <class>.
       See Class.

       PGP: Pretty Good Privacy. An authentication and encryption scheme.

       Primary Server: See Master Server.

       Punt Referral: A pointer to another server that is further up an
       RWhois tree. It is used to route a query up the tree. See Referral
       and RWhois Tree.

       Query: A command that a client sends to a server to access the data
       in an authority area.

       Query Routing: Redirecting a query to another server for resolution.
       See Query.

       Referral: A pointer to another server that is presumed to be closer
       to the desired data. It is used to route a query. See Query Routing.

       Referral Class: A standard class that contains referral information
       for an authority area. See Class and Referral.

       Replication: A server duplicating data from another server on a per-
       authority area basis. See Authority Area.

       Response: The information that a server returns to a client for a
       directive. See Directive.

       Result: The information that a server returns to a client for a
       query. It can be either the accessed data or referrals to other
       servers. See Query and Referral.

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    RFC 2167                    RWhois Protocol                    June 1997

       RWhois Tree: A data information tree of RWhois servers where the data
       is arranged hierarchically in the authority areas. See Authority
       Area.

       Schema: See Class.

       Secondary Server: See Slave Server.

       Slave Server: A server where the data is replicated from the master
       server for an authority area. It also answers authoritatively to
       queries in the authority area. It is also called a secondary server.
       See Master Server.

       SOA: Start Of Authority. Administrative variables, defined at the
       master server, to control replication for an authority area. See
       Master Server and Replication.

    Appendix B: RWhois ABNF

       This specification uses the Augmented Backus-Naur Form (ABNF)
       notation, as defined in Section 2 of [RFC 822].

       General Definitions

       Lexical Tokens

       alpha = "a".."z" / "A".."Z"
       digit = "0".."9"
       hex-digit = digit / "a".."f" / "A".. "F"
       id-char = alpha / digit / "_" / "-"
       any-char = <ASCII 1..255,
                  except LF (linefeed) and CR (carriage return)>
       dns-char = alpha / digit / "-"
       email-char = <see [RFC 822]>
       space = " "
       tab = <ASCII TAB (tab)>
       lf = <ASCII LF (linefeed)>
       cr = <ASCII CR (carriage return)>
       crlf = cr lf

       Grammar

       year = 4digit
       month = 2digit
       day = 2digit
       hour = 2digit
       minute = 2digit
       second = 2digit

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       milli-second = 3digit
       host-name = dns-char *(dns-char / ".")
       email = 1*email-char "@" host-name
       authority-area = (dns-char / ".") *(dns-char / "." / "/")
       object-id = 1*id-char "." authority-area
       host-port = (host-name / ip-address) ":" 1*5digit
       ip-address = 1*3digit "." 1*3digit "." 1*3digit "." 1*3digit
       class-name = 1*id-char
       attribute-name = 1*id-char
       attribute-value = 1*any-char
       time-stamp = year month day hour minute second milli-second
       on-off = "on" / "off"

       Note that the time-stamp must be in the Greenwich Mean Time (GMT)
       time zone.

       response = ok-response crlf / error-response crlf / info-response
       ok-response = "%ok"
       error-response = "%error" space error-code space error-text
       error-code = 3digit
       error-text = 1*any-char
       info-response = "%info" space "on" crlf *(*any-char crlf) "%info"
               space "off" crlf

       rwhois-banner = "%rwhois" space version-list space host-name
               [space implementation] crlf
       version-list = version *("," version)
       version = version-number [":" capability-id]
               / "V-1.5" ":" capability-id
       version-number = "V-" 1*digit "." 1*digit
       capability-id = response-id ":" extra-id
       response-id = 6hex-digit
       extra-id = 2hex-digit
       implementation = 1*any-char

       rwhois-protocol = client-sends / server-returns
       client-sends = *(directives / rwhois-query)
       server-returns = *(responses / rwhois-query-result)

       directives = rwhois-dir / class-dir / directive-dir / display-dir /
               holdconnect-dir / limit-dir / notify-dir / quit-dir /
               register-dir / schema-dir / security-dir / soa-dir /
               status-dir / xfer-dir / x-dir

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       responses = rwhois-response / class-response/ directive-response/
               display-response/ holdconnect-response/ limit-response/
               notify-response/ quit-response/ register-response/
               schema-response / security-response/ soa-response/
               status-response/ xfer-response/ x-response

       Required Directives

       rwhois

       rwhois-dir = "-rwhois" space version-number [space implementation]
                    crlf
       rwhois-response = "%rwhois" space version space host-name
               [space implementation] crlf

       Optional Directives

       class

       class-dir = "-class" space authority-area *(space class-name) crlf
       class-response = *class-record response
       class-record = *class-line "%class" crlf
       class-line = "%class" space class-name ":" "description" ":"
                    1*any-char crlf
          / "%class" space class-name ":" "version" ":" time-stamp crlf
          / "%class" space class-name ":" meta-field ":" meta-value crlf
       meta-field = 1*id-char
       meta-value = 1*any-char

       directive

       directive-dir = "-directive" *(space directive-name)crlf
       directive-name = 1*id-char
       directive-response = *directive-record response
       directive-record = "%directive" space "directive" ":"
               directive-name crlf *directive-line "%directive" crlf
       directive-line = "%directive" space "description" ":" 1*any-char crlf
               / "%directive" space attribute-name ":" attribute-value crlf

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       display

       display-dir = "-display" crlf
          / "-display" space display-name crlf
       display-name = 1*id-char
       display-response = *display-record response
       display-record = "%display" space "name" ":" display-name crlf
       *display-line "%display" crlf
       display-line = "%display" space attribute-name ":" attribute-value
                      crlf

       holdconnect

       holdconnect-dir = "-holdconnect" space on-off crlf
       holdconnect-response = response

       limit

       limit-dir = "-limit" space 1*digit crlf
       limit-response = response

       notify

       notify-dir = "-notify" space "badref" space referral-query crlf
               / "-notify" space "recurref" space referral-query crlf
               / "-notify" space "update" space host-port ":" authority-area
                 crlf
               / "-notify" space "inssec" space host-port ":" authority-area
                 crlf
               / "-notify" space "delsec" space host-port ":" authority-area
                 crlf
       referral-query = referral-url space [class-name space] query
       notify-response = response

       See the query section for the definitions of referral-url and query.

       quit

       quit-dir = "-quit" crlf
       quit-response = response

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       register

       register-dir = register-on space "add" space maintainer-id crlf
               register-add register-off
               / register-on space "mod" space maintainer-id crlf
                       register-mod register-off
               / register-on space "del" space maintainer-id crlf
                       register-del register-off
       register-on = "-register" space "on"
       register-off = "-register" space "off" crlf
       register-add = 1*(register-line crlf)
       register-mod = 1*(register-line crlf) "_NEW_" crlf
                      1*(register-line crlf)
       register-del = 1*(register-line crlf)
       maintainer-id = email
       register-line = attribute-name ":" attribute-value
       register-on-response = response
       register-off-response = "%register" space "ID" ":" object-id crlf
                               response
               / "%register" space "Updated" ":" time-stamp crlf response
               / response

       schema

       schema-dir = "-schema" space authority-area *(space class-name) crlf
       schema-response = *schema-record response
       schema-record = *schema-line "%schema" crlf
       schema-line = "%schema" space class-name ":" attribute-name ":"
               attribute-value crlf

       security

       security-dir = "-security" space "on" space direction space
               security-method [space security-data] crlf security-payload
               ["-security" space "off" crlf]
       direction = "request" / "response"
       security-method = "password" / "pgp" / 1*id-char
       security-data = password-data / pgp-data / 1*any-char
       password-data = 1*any-char
       pgp-data = "signed" / "encrypt" [space key-id] / "signed-encrypt"
                  [space key-id]
       security-payload = *(*any-char crlf)
       security-response = response

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       soa

       soa-dir = "-soa" *(space authority-area) crlf
       soa-response = *soa-record response
       soa-record = *soa-line "%soa" crlf
       soa-line = "%soa" space "authority" ":" authority-area crlf
          / "%soa" space "ttl" ":" 1*digit crlf
          / "%soa" space "serial" ":" time-stamp crlf
          / "%soa" space "refresh" ":" 1*digit crlf
          / "%soa" space "increment" ":" 1*digit crlf
          / "%soa" space "retry" ":" 1*digit crlf
          / "%soa" space "tech-contact" ":" email crlf
          / "%soa" space "admin-contact" ":" email crlf
          / "%soa" space "hostmaster" ":" email crlf
          / "%soa" space "primary" ":" host-port crlf
          / "%soa" space attribute-name ":" attribute-value crlf

       status

       status-dir = "-status" crlf
       status-response = *status-line response
       status-line = "%status" space "limit" ":" 1*digit crlf
          / "%status" space "holdconnect" ":" on-off crlf
          / "%status" space "forward" ":" on-off crlf
          / "%status" space "authority" ":" 1*digit crlf
          / "%status" space "display" ":" 1*any-char crlf
          / "%status" space "contact" ":" email crlf
          / "%status" space attribute-name ":" attribute-value crlf

       xfer

       xfer-dir = "-xfer" space authority-area *attribute-def
               [space serial-number] crlf
       attribute-def = [space "class=" class-name]
                       *(space "attribute=" attribute-name)
       serial-number = time-stamp
       xfer-response = *xfer-record response
       xfer-record = *xfer-line "%xfer" crlf
       xfer-line = "%xfer" space class-name ":" attribute-name ":"
                   attribute-value crlf

       X

       x-dir = "-X-" x-directive [space *[x-arguments]] crlf
       x-directive = 1*id-char
       x-arguments = *any-char
       x-response = *(*any-char crlf) response

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       Query

       rwhois-query = [class-name space] query crlf
       query = query-string / attribute-query / query bin-boolean query
       query-char = <any-char, except """, space, tab>
       quoted-query-char = query-char / space / tab / "
       query-string = 1*query-char ["*"] / """ 1*quoted-query-char ["*"] """
       attribute-query = attribute-name "=" query-string
       bin-boolean = "and" / "or"

       rwhois-query-result = *(query-record / referral-record) response
       query-record = 1*query-line crlf
       query-line = class-name ":" attribute-name [";" type-char] ":"
               attribute-value crlf
       type-char = "T" / "I" / "S"
       referral-record = 1*(referral-line crlf)
       referral-line = "%referral" space referral-url
       referral-url = "rwhois" ":" "//" host-port "/" "auth-area="
                      authority-area

    Appendix C: Error Codes

       When a server fails to run a command (directive or query), it returns
       an error response. The ABNF for an error response is as follows.

       error-response = "%error" space error-code space error-text
       error-code = 3digit
       error-text = 1*any-char

       An error text may be modified, but its meaning must remain the same.
       The server may append additional information to it, for example
       "%error 333 Not master for authority area: foobar.com".

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       The following table describes the possible digits in the first,
       second, and third positions of an error code.
        XXX    Description
        1XX    Information only, no action required
        2XX    Information, action required
        3XX    Specific command error, retry that command or try another one
        4XX    Serious for current command, may correct with another command
        5XX    Fatal, must disconnect
        X0X    System wide, no specific command
        X1X    System wide, no specific command
        X2X    Registration error
        X3X    Specific command
        X4X    Specific command
        X5X    Specific command
        X6X    Extended message (version specific)
        XXX    Sequential order

       The following table gives an ordered list of RWhois error codes.
       These codes may be extended with implementation- specific codes. An
       implementation- specific code must have a "6" in the second position.

        Code    Text
        120     Registration deferred
        130     Object not authoritative
        230     No objects found
        300     Not compatible with version
        320     Invalid attribute
        321     Invalid attribute syntax
        322     Required attribute missing
        323     Object reference not found
        324     Primary key not unique
        325     Failed to update outdated object
        330     Exceeded maximum objects limit
        331     Invalid limit
        332     Nothing to transfer
        333     Not master for authority area
        336     Object not found
        338     Invalid directive syntax
        340     Invalid authority area
        341     Invalid class
        342     Invalid host/port
        350     Invalid query syntax
        351     Query too complex
        352     Invalid security method
        353     Authentication failed
        354     Encryption failed
        400     Directive not available
        401     Not authorized for directive

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        402     Unidentified error
        420     Registration not authorized
        436     Invalid display format
        500     Memory allocation problem
        501     Service not available
        502     Unrecoverable error
        503     Idle time exceeded

       The following error codes, defined in [RFC 1714], have been made
       obsolete:  100, 200, 231, 334, 335, 337, 421, 431, 432, 433, 434,
       460, 461, and 530.

    Appendix D: Capability ID

       The capability ID encodes which directives are implemented in the
       server.  To create a capability ID, perform a logical OR on all the
       hexadecimal numbers corresponding to the implemented directives. The
       resulting number is used in the banner, which is sent by the server
       after opening a connection and as a response to the "-rwhois"
       directive. The eight most significant bits of the capability ID are
       reserved for future use:

        class        000001h
        directive    000002h
        display      000004h
        forward      000008h
        holdconnect  000010h
        limit        000020h
        notify       000040h
        quit         000080h
        register     000100h
        schema       000200h
        security     000400h
        soa          000800h
        status       001000h
        xfer         002000h
        X            004000h

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    Appendix E: Schema Definitions

    Attribute Definition Model

     Name         Type  Description

     Attribute    N     This is the name of the attribute.

     Description  S     This is a free-form description of the attribute.

     Type         T     This is a parameter that broadly indicates the use
                        of the attribute to the protocol. There are three
                        standard types: TEXT, ID, and SEE-ALSO. The default
                        is TEXT, which indicates that the value is a text
                        string.  ID indicates that the attribute contains
                        the ID of another RWhois object. This type of
                        attribute is used for database normalization. SEE-
                        ALSO indicates that the attribute contains a pointer
                        (a Uniform Resource Identifier (URI)) to some other
                        kind of external data; for example, a World Wide Web
                        page or FTP site.

     Format       S     This is an interpretable string that describes the
                        acceptance format of the value. The server (and
                        optionally the client) should match the value to the
                        format string to determine if the value is
                        acceptable.  The format of this property is a
                        keyword indicating the syntax of the format string,
                        followed by a colon, followed by the format string
                        itself. Currently, the only keyword recognized is
                        "re" for POSIX.2 extended regular expressions.

     Indexed      B     This is a true or false flag that indicates that
                        this attribute should be indexed (and therefore able
                        to be searched).

     Required     B     This is a true or false flag that indicates that
                        this attribute must have a value.

     Multi-Line   B     This is a true or false flag that indicates that
                        this attribute may have multiple instances in an
                        object; all the instances are to be considered as
                        multiple lines of the same attribute instance.

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     Repeatable   B     This is a true or false flag that indicates that
                        there may be multiple instances of this attribute in
                        a class and each instance is to be interpreted as a
                        separate instance (in contrast to Multi-Line). This
                        flag is mutually exclusive with Multi-Line: if
                        Multi-Line is true, then Repeatable must be false
                        and vice versa.

     Primary      B     This is a true or false flag that indicates that
                        this attribute is a primary key. If more than one
                        attribute in a class is marked as primary, then
                        these attributes together form a single primary key.
                        The primary key is intended to be used to force
                        uniqueness among class instances. Therefore, there
                        can be only one instance of a primary key in a
                        database. The Primary flag implies that the
                        attribute is also required.

     Hierarchical B     This is a true or false flag that indicates that
                        this attribute is lexically hierarchical.

     Private      B     This is a true or false flag that indicates whether
                        or not this attribute is private (that is, publicly
                        not viewable). It defaults to false. If it is true,
                        then only the clients that satisfy the
                        authentication/encryption requirements of a guardian
                        are able to view the attribute-value pair.

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       Type is defined as follows:

        Type  ABNF Definition

         B     "ON" / "OFF"
         N     1*id-char
         S     1*any-char
         T     "ID" / "SEE-ALSO" / "TEXT"

       Base Class

     Name       Type   Required  RepeatableDescription

     Class-Name TEXT   Y         N         This attribute is the name of the
                                           class to which the object
                                           belongs.

     Auth-Area  TEXT   Y         N         This attribute is the name of the
                                           authority area to which the
                                           object belongs.

     ID         TEXT   Y         N         This attribute is the universal
                                           identifier of the object.

     Updated    TEXT   Y         N         This attribute is a time/date
                                           stamp that indicates the time of
                                           last modification of the object.

     Guardian   ID     N         Y         This attribute is a link to a
                                           guardian object. Its value is the
                                           ID of a guardian object.

     Private    TEXT   N         N         This attribute is a true or false
                                           flag that indicates whether or
                                           not an object is private (that
                                           is, publicly not viewable). It
                                           defaults to false. If it is
                                           true, then only the clients
                                           that satisfy the
                                           authentication/encryption
                                           requirements of one of the
                                           object's guardians are able to
                                           view the object. If the object
                                           is publicly viewable, then the
                                           Private attribute property of
                                           each of its attributes still
                                           applies.

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     TTL        TEXT   N         N         This attribute is the
                                           "time-to-live" of a given object.
                                           It is included only if an object
                                           has a different time-to-live than
                                           the default given in the Start of
                                           Authority information. Its value
                                           is specified in seconds.

    Appendix F: Changes RWhois V1.0 - V1.5

       General

          * Multiple authority areas per server.
          * Data replication.
          * Revised schema model.
          * Revised query routing rules.
          * Revised error codes.
          * Removed unnecessary spaces in responses and results.

       Directives

          * Class: New. Returns meta-information for a class.
          * Display: Can return supported display formats.
          * Load: Obsolete.
          * Notify: Syntax change.
          * Private: Obsolete.
          * Register: Syntax change.
          * Schema: Syntax change.
          * Security: Obsoletes Private.
          * Xfer: Syntax change.

       Query

          * Display option removed.
          * Output format: Only the dump format is standard; optional type
            character added.
          * Attribute-restricted query.
          * Revised referral syntax.

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