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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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
[email protected]
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:
[email protected]
C -register off
S %register ID:23456789.a.com
S %register Updated:19961205224403000
S %ok
# Modify an object.
C -register on mod
[email protected]
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:
[email protected]
C -register off
S %ok
# Delete an object.
C -register on del
[email protected]
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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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
[email protected]
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:
[email protected]
S %soa admin-contact:
[email protected]
S %soa hostmaster:
[email protected]
S %soa primary:rs.internic.net:4321
S %soa
S %ok
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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:
[email protected]
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
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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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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.
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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
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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:
[email protected]
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:
[email protected]
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:
[email protected]
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:
[email protected]
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
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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
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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:
[email protected]
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.
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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".
Williamson, et. al. Informational [Page 46]
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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".
Williamson, et. al. Informational [Page 47]
RFC 2167 RWhois Protocol June 1997
# 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.
Williamson, et. al. Informational [Page 53]
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 (
[email protected])
Mark Kosters (
[email protected])
David Blacka (
[email protected])
Jasdip Singh (
[email protected])
Koert Zeilstra (
[email protected])
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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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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