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INTERNET-DRAFT                                             Simon Butcher
Expires April 2004                               Alien Internet Services
                                                            October 2003


                  Uniform Resource Locator Schemes for
                      Internet Relay Chat Servers
                     <draft-butcher-irc-url-00.txt>


Status of this Memo

   This document is an Internet-Draft and is subject to all provisions
   of Section 10 of RFC2026.  Distribution of this document is
   unlimited.  Comments should be sent to the author.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as
   Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/1id-abstracts.html

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html


Abstract

   This document specifies two URL (Uniform Resource Locator) schemes,
   using the URI (Uniform Resource Indicator) names "irc" and "ircs",
   for the location of IRC (Internet Relay Chat) servers.  These URLs
   allow for easy location of an IRC server, optionally also specifying
   an IRC channel to join or person to contact upon connection.











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1.  Introduction

   Since its introduction, Internet Relay Chat (IRC) has become widely
   known and used within the Internet Community as a real-time chat
   medium.  IRC networks are steadily growing larger, not only with
   regards to the number of regular uses, but also the number of
   channels and servers required to support the demand.

   Due to the nature of IRC as a simple real-time chat service, it has
   been known to be used for a wide variety of uses such as software
   support, job interviews, and of course just for a casual chat.

   While IRC is progressing, the need for an appropriate Uniform
   Resource Locator (URL) scheme has become apparent.  Applications for
   such a scheme would range quite widely, including IRC network server
   lists on a website, software support contact details, or even a
   meeting location with an e-mail including a specific IRC channel.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

   In this document, the term "client" is defined as the IRC client
   software, and the term "user" is the end-user of that software.


2.  URL Definition

   An IRC URL begins with either the Uniform Resource Identifiers (URIs)
   "irc" or "ircs", denoting normal and secured connections
   respectively.  Normal sessions are via the existing transport, as
   defined in [RFC2812], and secured sessions are the same, only via a
   secure transport layer such as [TLS] (or [SSL], the predecessor to
   TLS).

   The URL scheme for IRC follows the Generic URL Syntax, defined in
   [RFC2396].














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2.1.  ABNF Syntax

   The following is the definition for an IRC URL in [ABNF] grammar:

      ircURL   = type "://" location "/" [ channel ] [ options ]

      type     = "irc" / "ircs"

      location = [ authinfo "@" ] hostport
                     ; See Section 3.2.2 of [RFC2396] for
                     ; the definition of 'hostport'.

      authinfo = [ nickname *2( ";" nickname ) ] [ ":" password ]

      nickname = ALPHA / DIGIT / %x23-25 / %x2A-2F
                     ; Further restrictions may apply upon
                     ; connection, depending on the server.
                     ; Some common nickname characters must be
                     ; encoded, as per recommendations in Section
                     ; 2.4.3 in [RFC2396].

      password = ALPHA / DIGIT / %x23-24 / %x2A-2F / ";" / "=" / "?"

      channel  = ALPHA / DIGIT / %x23-24 / %x2A-2F
                     ; See [RFC2811] for the definition of
                     ; a channel.

      options  = "?" option *( "&" option )

      option   = optname [ "=" optvalue ]

      optname  = ALPHA

      optvalue = ALPHA / DIGIT / %x23-24 / %x2A-2F / ":" / ";" / "@"
                     ; Other characters (such as [Unicode]
                     ; characters in [UTF-8]) must be escaped
                     ; as per rules in Section 2.2.5 of [RFC2718].
                     ; See also Section 4 of this document.

   The use of the "%" character (%x25) is used to facilitate escaped
   characters.  Should the "%" character itself be needed, it must be
   escaped, such as "%25".  The use of spaces, escaped (%20) or
   otherwise, SHOULD NOT be allowed for channel names or nicknames, as
   they are currently unsupported by existing IRC protocols.







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2.2.  Authentication

   Multiple nicknames MAY be specified, and pending any error or lack of
   availability, the IRC client software MAY request the next nickname
   in the list.

   Clients MUST NOT accept any more than three (3) nicknames, and any
   more nicknames specified MUST be ignored to curtail potential abuse.

   Clients may only attempt to use alternative nicknames given during
   the one connection.  Clients MUST NOT reconnect to the server to try
   alternative nicknames.

   Should the client run out of alternative nicknames to try, but the
   server is willing to accept another attempt, the client MAY either
   disconnect from the server and show the user an error message, or
   prompt the user for another nickname to try.

   The use of passwords is not recommended, as they present a
   significant security problem.  They are allowed purely for
   convenience.  Users of the password field must be aware of the
   security issues discussed in Section 6 of this document.


2.3.  Server Ports

   Special consideration must be given to URLs without ports specified.
   Almost all IRC servers are contactable on a variety of standard ports
   as allocated by the IANA.  Should an IRC URL be specified without a
   port, a client SHOULD try a number of standard ports:

      - For the "irc" URI, it is RECOMMENDED that the server is attempts
        connection to the ports 194, 6665, 6666, 6667, 6668 and 6669.

      - For the "ircs" URI, it is RECOMMENDED that the default port used
        is 994.  User-space ports (those above port 1023) may have
        questionable authenticity, and SHOULD NOT be used unless
        explicitly specified.

   Port numbers shown here are in decimal, and have been assigned by the
   IANA.










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2.4.  Channels

   For compatibility with older implementations, and to allow
   simplification of the specification, channels MAY be specified
   without the use of the "channel" option detailed in Section 2.5.1.

   Only one channel can be specified, and this facility has the same
   functionality as the "channel" option.  See Section 3 of this
   document for examples of the equivalence between this and the
   "channel" option in Section 2.5.1.


2.5.  Additional Options

   Additional options may be added to control what action the client
   software MAY take following connection to the IRC server.
   Unsupported options should simply be ignored.

   These options listed here may be expanded on at a later date by
   updated RFC's.


2.5.1.  The "channel" Option

   This instructs the client to join the specified channel, allowing the
   user to participate in discussions within the channel.

   The value given with the channel option is a channel name, and
   optionally a "key" (see Section 4.2.10 of [RFC2811]).  Its value can
   be defined in [ABNF] as follows:

      optvalue = name [ "," key ]

   See Section 2.1 of this document for information on acceptable
   characters.  The "," character is not allowed in either the channel
   name, or key, unless it is escaped ("%x2C").

   The number of channels which can be joined at once is normally
   restricted by the server, but no hard-limit is given by this
   specification as this is a matter of individual server policy.  As
   such, multiple "channel" options may be given.

   An automated message MUST NOT be sent to the channel upon joining it.

   It is NOT RECOMMENDED to use the channel key feature.  Please see
   Section 6 of this document.  If a key is required to join a channel,
   and one is not given, the IRC client MAY wish to prompt the user for
   the key.



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2.5.2.  The "query" Option

   For each "query" option, the client is requested to open some
   interface where by users may type a message to the given query
   target.  For example, the client may open up a window where messages
   may be typed to, and received from the target.

   Some clients may not have the ability to open up a specific window or
   dialogue box.  These clients MAY prompt the user for a message to be
   sent to the target, or otherwise this option MAY be ignored and hence
   unsupported.

   The option value is the same as the message target value specified in
   Section 3.3.1 of [RFC2812], except that the client MUST only accept
   one target.  Multiple targets per "query" option MUST NOT be
   accepted, and the entire query MUST be considered invalid and
   ignored.

   A message MUST NOT be automatically sent to the target, simply an
   interface created to allow the user to send a message to the target.

   The IRC client software MAY wish to check the availability of the
   target prior to opening the interface if inclined to do so, however
   any method of testing the availability MUST NOT generate any
   automatic message being sent to the target.

   Multiple targets MAY be referenced with multiple query options,
   however in order to reduce the potential for abuse, it is RECOMMENDED
   that additional query options are ignored.  There are valid reasons
   for having multiple targets, and abuse is minimal as no messages are
   sent to the targets.


3.  Examples

   While examples of every situation cannot be shown here because of
   space considerations, the following examples provide a rough overview
   of how the IRC URL can be used.

      <irc://irc.undernet.org/>

   In its simplest form, the above complete URL can be used to direct a
   client to a specific IRC server, which in this case is
   "irc.undernet.org".  The client should presume to use default port
   settings.

      <irc://pickle@irc.efnet.org:6667/>




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   The above URL specifies that the IRC client should try to connect to
   "irc.efnet.org" on the port 6667, rather than use whatever is
   considered the default.  It also tells the IRC client it should try
   to use a nickname of "pickle", if it is available.

      <irc://%C4%B0dil;idil@irc.austnet.org/>

   This shows a properly [UTF-8] encoded URL, specifying the nickname
   Idil (with the first character being a Turkish Latin capital letter
   "I" with a dot above it, [Unicode] codepoint U+0130).  Failing that,
   the second nickname, "idil", may be used if the first one is
   rejected, perhaps by an older IRC server.

      <irc://pickle:secret@172.16.0.12:194/>

   The above URL will instruct the IRC client to connect to a server
   with the address 172.16.0.12, which is an IRC server that is
   presumably password protected.  The client should request to use the
   nickname "pickle", with the password "secret" to authenticate the
   session to the remote server. This URL also enforces the standard IRC
   port, 194, and will stop IRC clients from hunting for ports.

      <irc://irc.ircnet.net/#worldchat>
      <irc://irc.ircnet.net/%23worldchat>
      <irc://irc.ircnet.net/?channel=%23worldchat>

   All three of these URLs connects to the IRCnet network, and will join
   the client to the channel "#worldchat" upon connection.

      <irc://irc.alien.net.au/?query=pickle&channel=%2Bprivate,foo>

   This will connect to the server "irc.alien.net.au" and will provoke
   the client to open up a window (or similar) associated with sending
   messages to the nickname 'pickle'.  It will also join the channel
   "+private" using the channel key "foo".

      <irc://irc.austnet.org/%23melbourne?channel=%23sydney>

   This will connect to AUSTnet and join two channels, "#melbourne" and
   "#sydney".

      <irc://irc.undernet.org/?query=pickle%25butcher.id.au>

   This will open a dialogue box prepared to send a message to
   "pickle%butcher.id.au".  Please refer to Section 3.3.1 of [RFC2812]
   for more details.





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4.  Internationalisation Considerations

   With the inevitable adoption of [Unicode] on IRC, and indeed the
   Internet as a whole, URLs MUST be encoded using the [UTF-8] character
   set, with potentially unsafe octets encoded using %HH notation (where
   HH is a hexadecimal value), as per Section 2.2.5 of [RFC-2718].

   For example, the word for "alias" in Japanese, using Unicode code-
   points, is U+5225 U+540D.  Correctly encoded, this would appear in
   the URL as: "%E5%88%A5%E5%90%8D".  An example of this use in action
   can be found in Section 3.


5.  Interoperability Considerations

   Many existing implementations fail to acknowledge the correct use of
   the generic URL syntax defined in [RFC2396], but continue to use the
   format regardless.

   Some implementations do not take into consideration the use of prefix
   characters on channels names, as defined by [RFC2811], and therefore
   cannot correctly reference channels appropriately.  Software SHOULD
   NOT guess the channel type, or hence the channel's prefix character,
   unless the probability of an accurate guess is 100% (for example, the
   server only supports one type of channel).

   Some current implementations will need slight modification to accept
   the extended format defined in this specification, however most
   implementations which parse the URL in a standard form will continue
   to work.

   The majority of incongruities are simply caused by the problem of
   developers ignoring RFC-2396.

   The use of the channel name without specifying the channel option is
   to both maintain compatibility with the existing implementations,
   whilst providing an abbreviated form, similar to the design of the
   "mailto:" scheme defined by [RFC2368].


6.  Security Considerations

   Security problems arise only when the authentication portion of the
   URL is used, or channel keys are given.  While the use of the
   password/key extensions is considered to be rare, they have been
   included for completeness.

   As the passwords and channel keys are unfortunately in clear-text,



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   any user using the IRC URL should be aware of obvious insecurities.

   Furthermore, it is RECOMMENDED that user software does not
   automatically initiate the connection specified by the URL without
   the knowledge and consent of the user.  To do so would open the
   implementation up to a variety of malicious activities including, but
   not limited to, the purposes of direct advertising or channel
   advertising (also known as "spam") by way of pop-ups.

   When connecting using a secure connection ("ircs://"), user-space
   ports (those above port 1023) SHOULD NOT be used automatically, as
   their authority is questionable.  If a secure connection cannot be
   established, the client MUST either give up, or prompt the user
   before attempting an insecure ("irc://") connection.

   Beyond this, there are security concerns with regards with associated
   protocols, including IRC and TLS, which MUST be taken into
   consideration, but are beyond the scope of this document.

7.  Acknowledgments

   Thanks must go to Khaled Mardam-Bey for his early implementation in
   his software, "mIRC", which provided the inspiration to clarify the
   specification.

   I would also like to acknowledge the members of the IRC development
   community who encouraged me to publish this draft, after more than 18
   months of pretermission.























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8.  References


   [ABNF]    Crocker, D., and Overell, P., "Augmented BNF for Syntax
             Specifications: ABNF", RFC 2234, November 1997.

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2368] Hoffman, P., Masinter, L., Zawinski, J., "The mailto URL
             scheme", RFC 2368, July 1998.

   [RFC2396] Berners-Lee, T, Fielding, T., Masinter, L., "Uniform
             Resource Identifiers (URI): Generic Syntax", RFC 2396,
             August 1998.

   [RFC2718] Masinter, L., Alvestrand, H., Zigmond, D., Petke, R.,
             "Guidelines for new URL Schemes", RFC 2718, November 1999.

   [RFC2811] Kalt, C., "Internet Relay Chat: Channel Management", RFC
             2811, April 2000.

   [RFC2812] Kalt, C., "Internet Relay Chat: Client Protocol", RFC 2819,
             April 2000.

   [SSL]     Hickman, K., "The SSL Protocol", Netscape Communications
             Corp., February 9, 1995.

   [TLS]     Dierks, T. and Allen, C., "The TLS Protocol Version 1.0",
             RFC 2246, January 1999.

   [Unicode] The Unicode Consortium.  The Unicode Standard, Version
             4.0.0, (Reading, MA, Addison-Wesley, 2003. ISBN
             0-321-18578-1).

   [UTF-8]   Yergeau, F., "UTF-8, a transformation format of ISO 10646",
             RFC 2279, January 1998.














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9.  Author's Address

   Simon Butcher
   Alien Internet Services

   PO Box 7041
   Croydon South
   VIC  3136
   Australia

   Phone: +61-3-9879-8052
   Fax:   +61-3-9893-2793
   Email: simonb@alien.net.au


Document Expiration and Filename

   Please note that this is a draft document and it shall expire April
   2004.  Its filename is draft-butcher-irc-url-00.txt
































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