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<title>Internet Relay Chat: Client-to-Client Protocol (CTCP)</title>
<meta content="Mantas Mikulėnas" name="author">
<meta content="Daniel Oakley" name="author">
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This document describes the Client-to-Client Protocol (CTCP), which lets Internet Relay Chat (IRC) clients send each other messages that get displayed or responded to in special ways. CTCP has been widely implemented, with most clients supporting it natively. This document outlines how to implement CTCP and the most common messages.
This document updates RFCs 1459 and 2812.
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<table class="ears">
<thead><tr>
<td class="left">Internet-Draft</td>
<td class="center">IRC CTCP</td>
<td class="right">May 2021</td>
</tr></thead>
<tfoot><tr>
<td class="left">Mikulėnas & Oakley</td>
<td class="center">Expires 24 November 2021</td>
<td class="right">[Page]</td>
</tr></tfoot>
</table>
<div id="external-metadata" class="document-information"></div>
<div id="internal-metadata" class="document-information">
<dl id="identifiers">
<dt class="label-workgroup">Workgroup:</dt>
<dd class="workgroup">Network Working Group</dd>
<dt class="label-internet-draft">Internet-Draft:</dt>
<dd class="internet-draft">draft-oakley-irc-ctcp-latest</dd>
<dt class="label-updates">Updates:</dt>
<dd class="updates">
<a href="https://www.rfc-editor.org/rfc/rfc1459" class="eref">1459</a>, <a href="https://www.rfc-editor.org/rfc/rfc2812" class="eref">2812</a> (if approved)</dd>
<dt class="label-published">Published:</dt>
<dd class="published">
<time datetime="2021-05-23" class="published">23 May 2021</time>
</dd>
<dt class="label-intended-status">Intended Status:</dt>
<dd class="intended-status">Informational</dd>
<dt class="label-expires">Expires:</dt>
<dd class="expires"><time datetime="2021-11-24">24 November 2021</time></dd>
<dt class="label-authors">Authors:</dt>
<dd class="authors">
<div class="author">
<div class="author-name">M. Mikulėnas</div>
<div class="org">Independent</div>
</div>
<div class="author">
<div class="author-name">D. Oakley, <span class="editor">Ed.</span>
</div>
<div class="org">ircdocs</div>
</div>
</dd>
</dl>
</div>
<h1 id="title">Internet Relay Chat: Client-to-Client Protocol (CTCP)</h1>
<section id="section-abstract">
<h2 id="abstract"><a href="#abstract" class="selfRef">Abstract</a></h2>
<p id="section-abstract-1">This document describes the Client-to-Client Protocol (CTCP), which lets Internet Relay Chat (IRC) clients send each other messages that get displayed or responded to in special ways. CTCP has been widely implemented, with most clients supporting it natively. This document outlines how to implement CTCP and the most common messages.<a href="#section-abstract-1" class="pilcrow">¶</a></p>
<p id="section-abstract-2">This document updates RFCs 1459 and 2812.<a href="#section-abstract-2" class="pilcrow">¶</a></p>
</section>
<div id="status-of-memo">
<section id="section-boilerplate.1">
<h2 id="name-status-of-this-memo">
<a href="#name-status-of-this-memo" class="section-name selfRef">Status of This Memo</a>
</h2>
<p id="section-boilerplate.1-1">
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.<a href="#section-boilerplate.1-1" class="pilcrow">¶</a></p>
<p id="section-boilerplate.1-2">
Internet-Drafts are working documents of the Internet Engineering Task
Force (IETF). Note that other groups may also distribute working
documents as Internet-Drafts. The list of current Internet-Drafts is
at <span><a href="https://datatracker.ietf.org/drafts/current/">https://datatracker.ietf.org/drafts/current/</a></span>.<a href="#section-boilerplate.1-2" class="pilcrow">¶</a></p>
<p id="section-boilerplate.1-3">
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."<a href="#section-boilerplate.1-3" class="pilcrow">¶</a></p>
<p id="section-boilerplate.1-4">
This Internet-Draft will expire on 24 November 2021.<a href="#section-boilerplate.1-4" class="pilcrow">¶</a></p>
</section>
</div>
<div id="copyright">
<section id="section-boilerplate.2">
<h2 id="name-copyright-notice">
<a href="#name-copyright-notice" class="section-name selfRef">Copyright Notice</a>
</h2>
<p id="section-boilerplate.2-1">
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.<a href="#section-boilerplate.2-1" class="pilcrow">¶</a></p>
<p id="section-boilerplate.2-2">
This document is subject to BCP 78 and the IETF Trust's Legal
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publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with
respect to this document.<a href="#section-boilerplate.2-2" class="pilcrow">¶</a></p>
</section>
</div>
<div id="toc">
<section id="section-toc.1">
<a href="#" onclick="scroll(0,0)" class="toplink">▲</a><h2 id="name-table-of-contents">
<a href="#name-table-of-contents" class="section-name selfRef">Table of Contents</a>
</h2>
<nav class="toc"><ul class="compact toc ulEmpty">
<li class="compact toc ulEmpty" id="section-toc.1-1.1">
<p id="section-toc.1-1.1.1" class="keepWithNext"><a href="#section-1" class="xref">1</a>. <a href="#name-introduction" class="xref">Introduction</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.2">
<p id="section-toc.1-1.2.1" class="keepWithNext"><a href="#section-2" class="xref">2</a>. <a href="#name-protocol-structure" class="xref">Protocol Structure</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.3">
<p id="section-toc.1-1.3.1" class="keepWithNext"><a href="#section-3" class="xref">3</a>. <a href="#name-message-syntax" class="xref">Message Syntax</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.4">
<p id="section-toc.1-1.4.1"><a href="#section-4" class="xref">4</a>. <a href="#name-messages" class="xref">Messages</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.5">
<p id="section-toc.1-1.5.1"><a href="#section-5" class="xref">5</a>. <a href="#name-acknowledgements" class="xref">Acknowledgements</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.6">
<p id="section-toc.1-1.6.1"><a href="#section-6" class="xref">6</a>. <a href="#name-security-considerations" class="xref">Security Considerations</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.7">
<p id="section-toc.1-1.7.1"><a href="#section-7" class="xref">7</a>. <a href="#name-iana-considerations" class="xref">IANA Considerations</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.8">
<p id="section-toc.1-1.8.1"><a href="#section-8" class="xref">8</a>. <a href="#name-normative-references" class="xref">Normative References</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.9">
<p id="section-toc.1-1.9.1"><a href="#section-appendix.a" class="xref">Appendix A</a>. <a href="#name-message-list" class="xref">Message List</a></p>
<ul class="compact toc ulEmpty">
<li class="compact toc ulEmpty" id="section-toc.1-1.9.2.1">
<p id="section-toc.1-1.9.2.1.1"><a href="#section-a.1" class="xref">A.1</a>. <a href="#name-action" class="xref">ACTION</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.9.2.2">
<p id="section-toc.1-1.9.2.2.1"><a href="#section-a.2" class="xref">A.2</a>. <a href="#name-clientinfo" class="xref">CLIENTINFO</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.9.2.3">
<p id="section-toc.1-1.9.2.3.1"><a href="#section-a.3" class="xref">A.3</a>. <a href="#name-dcc" class="xref">DCC</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.9.2.4">
<p id="section-toc.1-1.9.2.4.1"><a href="#section-a.4" class="xref">A.4</a>. <a href="#name-finger" class="xref">FINGER</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.9.2.5">
<p id="section-toc.1-1.9.2.5.1"><a href="#section-a.5" class="xref">A.5</a>. <a href="#name-ping" class="xref">PING</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.9.2.6">
<p id="section-toc.1-1.9.2.6.1"><a href="#section-a.6" class="xref">A.6</a>. <a href="#name-source" class="xref">SOURCE</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.9.2.7">
<p id="section-toc.1-1.9.2.7.1"><a href="#section-a.7" class="xref">A.7</a>. <a href="#name-time" class="xref">TIME</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.9.2.8">
<p id="section-toc.1-1.9.2.8.1"><a href="#section-a.8" class="xref">A.8</a>. <a href="#name-version" class="xref">VERSION</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.9.2.9">
<p id="section-toc.1-1.9.2.9.1"><a href="#section-a.9" class="xref">A.9</a>. <a href="#name-userinfo" class="xref">USERINFO</a></p>
</li>
</ul>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.10">
<p id="section-toc.1-1.10.1"><a href="#section-appendix.b" class="xref">Appendix B</a>. <a href="#name-change-history-rfc-editor-p" class="xref">Change History [RFC Editor: Please remove this section]</a></p>
</li>
<li class="compact toc ulEmpty" id="section-toc.1-1.11">
<p id="section-toc.1-1.11.1"><a href="#section-appendix.c" class="xref"></a><a href="#name-authors-addresses" class="xref">Authors' Addresses</a></p>
</li>
</ul>
</nav>
</section>
</div>
<div id="introduction">
<section id="section-1">
<h2 id="name-introduction">
<a href="#section-1" class="section-number selfRef">1. </a><a href="#name-introduction" class="section-name selfRef">Introduction</a>
</h2>
<p id="section-1-1">The core Internet Relay Chat (IRC) protocol as described in <span>[<a href="#RFC1459" class="xref">RFC1459</a>]</span> and <span>[<a href="#RFC2812" class="xref">RFC2812</a>]</span> does not provide a way to exchange computer-readable information directly between clients. The Client-to-Client Protocol (CTCP) lets them exchange messages that get processed, displayed or responded to in special ways.<a href="#section-1-1" class="pilcrow">¶</a></p>
<p id="section-1-2">CTCP can be used to request special formatting on messages, query other clients for metadata, and help initiate file transfers with other clients among other uses. This document covers the subset of CTCP which is commonly implemented, and clients implementing this specification are compatible with those implementing the protocol as described by older documents.<a href="#section-1-2" class="pilcrow">¶</a></p>
<p id="section-1-3">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 <span>[<a href="#RFC2119" class="xref">RFC2119</a>]</span>.<a href="#section-1-3" class="pilcrow">¶</a></p>
</section>
</div>
<div id="protocol-structure">
<section id="section-2">
<h2 id="name-protocol-structure">
<a href="#section-2" class="section-number selfRef">2. </a><a href="#name-protocol-structure" class="section-name selfRef">Protocol Structure</a>
</h2>
<p id="section-2-1">CTCP queries are sent with the PRIVMSG IRC command, and CTCP replies are sent with NOTICE command. To indicate a CTCP query or reply, the body of the message (the second parameter) begins with the CTCP delimiter.<a href="#section-2-1" class="pilcrow">¶</a></p>
<p id="section-2-2">Queries MAY be sent to channels. Replies MUST always be sent to the querying client only, not the channel.<a href="#section-2-2" class="pilcrow">¶</a></p>
<p id="section-2-3">Many servers implement filters so that only specific CTCP commands can be sent to channels. When this is done, channel operators can typically enable and disable this filtering with a channel mode.<a href="#section-2-3" class="pilcrow">¶</a></p>
</section>
</div>
<div id="message-syntax">
<section id="section-3">
<h2 id="name-message-syntax">
<a href="#section-3" class="section-number selfRef">3. </a><a href="#name-message-syntax" class="section-name selfRef">Message Syntax</a>
</h2>
<p id="section-3-1">The ABNF <span>[<a href="#RFC5234" class="xref">RFC5234</a>]</span> for CTCP message bodies is as follows:<a href="#section-3-1" class="pilcrow">¶</a></p>
<div class="artwork art-text alignCenter art-abnf" id="section-3-2">
<pre>
delim = %x01
command = 1*( %x02-09 / %x0B-0C / %x0E-1F / %x21-FF )
; any octet except NUL, delim, CR, LF, and SP
params = 1*( %x02-09 / %x0B-0C / %x0E-FF )
; any octet except NUL, delim, CR, and LF
body = delim command [ SP params ] [ delim ]
</pre><a href="#section-3-2" class="pilcrow">¶</a>
</div>
<p id="section-3-3">Commands are case-insensitive. When creating new CTCP commands, authors SHOULD use only alphanumeric characters for ease of implementation.<a href="#section-3-3" class="pilcrow">¶</a></p>
<p id="section-3-4">The final CTCP delimiter SHOULD be sent on outgoing messages for compatibility reasons, but software MUST accept incoming messages which lack it.<a href="#section-3-4" class="pilcrow">¶</a></p>
<p id="section-3-5">In message examples throughout this document, the CTCP delimiter is shown as <code>\x01</code>.<a href="#section-3-5" class="pilcrow">¶</a></p>
<p id="section-3-6">Here are two examples of valid CTCP queries and replies:<a href="#section-3-6" class="pilcrow">¶</a></p>
<div class="artwork art-text alignLeft" id="section-3-7">
<pre>
:alice!a@localhost PRIVMSG bob :\x01VERSION\x01
:bob!b@localhost NOTICE alice :\x01VERSION Snak for Mac 4.13\x01
:alice!a@localhost PRIVMSG #ircv3 :\x01PING 1473523796 918320
:bob!b@localhost NOTICE alice :\x01PING 1473523796 918320\x01
</pre><a href="#section-3-7" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="messages">
<section id="section-4">
<h2 id="name-messages">
<a href="#section-4" class="section-number selfRef">4. </a><a href="#name-messages" class="section-name selfRef">Messages</a>
</h2>
<p id="section-4-1">There is not a formal registry of CTCP message names, and CTCP responses are uniquely flexible. Clients that receive either unexpected messages or known messages with unexpected values SHOULD ignore them and send no response to the querying user.<a href="#section-4-1" class="pilcrow">¶</a></p>
</section>
</div>
<div id="acknowledgements">
<section id="section-5">
<h2 id="name-acknowledgements">
<a href="#section-5" class="section-number selfRef">5. </a><a href="#name-acknowledgements" class="section-name selfRef">Acknowledgements</a>
</h2>
<p id="section-5-1">Thanks to the IRCv3 group for giving feedback on this specification, and to Khaled Mardam-Bey for advice on client flood protection.<a href="#section-5-1" class="pilcrow">¶</a></p>
<p id="section-5-2">Thanks to Michael Sandrof for creating CTCP, Troy Rollo for creating the related DCC protocol, as well as Klaus Zeuge and Ben Mesander who wrote and revised related specifications.<a href="#section-5-2" class="pilcrow">¶</a></p>
<p id="section-5-3">Special thanks to dequis, Sadie Powell and James Wheare for help with this and related work.<a href="#section-5-3" class="pilcrow">¶</a></p>
</section>
</div>
<div id="security-considerations">
<section id="section-6">
<h2 id="name-security-considerations">
<a href="#section-6" class="section-number selfRef">6. </a><a href="#name-security-considerations" class="section-name selfRef">Security Considerations</a>
</h2>
<p id="section-6-1">CTCP messages are completely untrusted data and clients MUST NOT assume that they are well-formed or complete.<a href="#section-6-1" class="pilcrow">¶</a></p>
<p id="section-6-2">Older CTCP specifications describe quoting methods which are complex and not widely implemented. Implementations SHOULD NOT implement "low-level quoting" or "CTCP-level quoting" when parsing messages.<a href="#section-6-2" class="pilcrow">¶</a></p>
<p id="section-6-3">CTCP requests can be abused to flood clients off the server they are connected to. Clients SHOULD ignore or delay excessive incoming requests to protect against this.<a href="#section-6-3" class="pilcrow">¶</a></p>
<p id="section-6-4">Older CTCP specifications describe including more than one CTCP message inside a single PRIVMSG or NOTICE command. Implementations SHOULD NOT implement this form of CTCP parsing as it is not widely-implemented and may result in an implementation that can be more easily flooded off the server they are connected to.<a href="#section-6-4" class="pilcrow">¶</a></p>
</section>
</div>
<div id="iana-considerations">
<section id="section-7">
<h2 id="name-iana-considerations">
<a href="#section-7" class="section-number selfRef">7. </a><a href="#name-iana-considerations" class="section-name selfRef">IANA Considerations</a>
</h2>
<p id="section-7-1">This document has no actions for IANA.<a href="#section-7-1" class="pilcrow">¶</a></p>
</section>
</div>
<section id="section-8">
<h2 id="name-normative-references">
<a href="#section-8" class="section-number selfRef">8. </a><a href="#name-normative-references" class="section-name selfRef">Normative References</a>
</h2>
<dl class="references">
<dt id="RFC1459">[RFC1459]</dt>
<dd>
<span class="refAuthor">Oikarinen, J.</span> and <span class="refAuthor">D. Reed</span>, <span class="refTitle">"Internet Relay Chat Protocol"</span>, <span class="seriesInfo">RFC 1459</span>, <span class="seriesInfo">DOI 10.17487/RFC1459</span>, <time datetime="1993-05" class="refDate">May 1993</time>, <span><<a href="https://www.rfc-editor.org/info/rfc1459">https://www.rfc-editor.org/info/rfc1459</a>></span>. </dd>
<dd class="break"></dd>
<dt id="RFC2119">[RFC2119]</dt>
<dd>
<span class="refAuthor">Bradner, S.</span>, <span class="refTitle">"Key words for use in RFCs to Indicate Requirement Levels"</span>, <span class="seriesInfo">BCP 14</span>, <span class="seriesInfo">RFC 2119</span>, <span class="seriesInfo">DOI 10.17487/RFC2119</span>, <time datetime="1997-03" class="refDate">March 1997</time>, <span><<a href="https://www.rfc-editor.org/info/rfc2119">https://www.rfc-editor.org/info/rfc2119</a>></span>. </dd>
<dd class="break"></dd>
<dt id="RFC2812">[RFC2812]</dt>
<dd>
<span class="refAuthor">Kalt, C.</span>, <span class="refTitle">"Internet Relay Chat: Client Protocol"</span>, <span class="seriesInfo">RFC 2812</span>, <span class="seriesInfo">DOI 10.17487/RFC2812</span>, <time datetime="2000-04" class="refDate">April 2000</time>, <span><<a href="https://www.rfc-editor.org/info/rfc2812">https://www.rfc-editor.org/info/rfc2812</a>></span>. </dd>
<dd class="break"></dd>
<dt id="RFC5234">[RFC5234]</dt>
<dd>
<span class="refAuthor">Crocker, D., Ed.</span> and <span class="refAuthor">P. Overell</span>, <span class="refTitle">"Augmented BNF for Syntax Specifications: ABNF"</span>, <span class="seriesInfo">STD 68</span>, <span class="seriesInfo">RFC 5234</span>, <span class="seriesInfo">DOI 10.17487/RFC5234</span>, <time datetime="2008-01" class="refDate">January 2008</time>, <span><<a href="https://www.rfc-editor.org/info/rfc5234">https://www.rfc-editor.org/info/rfc5234</a>></span>. </dd>
<dd class="break"></dd>
<dt id="RFC5322">[RFC5322]</dt>
<dd>
<span class="refAuthor">Resnick, P., Ed.</span>, <span class="refTitle">"Internet Message Format"</span>, <span class="seriesInfo">RFC 5322</span>, <span class="seriesInfo">DOI 10.17487/RFC5322</span>, <time datetime="2008-10" class="refDate">October 2008</time>, <span><<a href="https://www.rfc-editor.org/info/rfc5322">https://www.rfc-editor.org/info/rfc5322</a>></span>. </dd>
<dd class="break"></dd>
</dl>
</section>
<div id="message-list">
<section id="section-appendix.a">
<h2 id="name-message-list">
<a href="#section-appendix.a" class="section-number selfRef">Appendix A. </a><a href="#name-message-list" class="section-name selfRef">Message List</a>
</h2>
<p id="section-appendix.a-1">This section is not exhaustive, and only lists those CTCP messages which are widely implemented across the IRC ecosystem. Clients MUST ONLY send params on a query if a params section is listed here.<a href="#section-appendix.a-1" class="pilcrow">¶</a></p>
<p id="section-appendix.a-2">The Query and Reply lines below represent variables by surrounding them with angle brackets.<a href="#section-appendix.a-2" class="pilcrow">¶</a></p>
<div id="action">
<section id="section-a.1">
<h2 id="name-action">
<a href="#section-a.1" class="section-number selfRef">A.1. </a><a href="#name-action" class="section-name selfRef">ACTION</a>
</h2>
<div class="artwork art-text alignLeft" id="section-a.1-1">
<pre>
Query: ACTION <text>
Reply: None
</pre><a href="#section-a.1-1" class="pilcrow">¶</a>
</div>
<p id="section-a.1-2">Clients which implement this message MUST display <text> as a third-person action or emote. Users typically use the <code>/me</code> command in their IRC clients to send this message.<a href="#section-a.1-2" class="pilcrow">¶</a></p>
<p id="section-a.1-3">If <text> is empty, clients SHOULD still include a single space after <code>ACTION</code> (i.e. an empty params section) to help ensure compatibility. Clients SHOULD correctly parse incoming ACTION messages with or without the params section. Leading spaces in <text> SHOULD NOT be stripped before being displayed to users.<a href="#section-a.1-3" class="pilcrow">¶</a></p>
<p id="section-a.1-4">ACTION is universally implemented and very commonly used. Clients MUST implement this CTCP message to effectively use IRC.<a href="#section-a.1-4" class="pilcrow">¶</a></p>
<p id="section-a.1-5">Examples:<a href="#section-a.1-5" class="pilcrow">¶</a></p>
<div class="artwork art-text alignLeft" id="section-a.1-6">
<pre>
Raw: :dan!user@host PRIVMSG #ircv3 :\x01ACTION does it!\x01
Formatted: * dan does it!
</pre><a href="#section-a.1-6" class="pilcrow">¶</a>
</div>
<div class="artwork art-text alignLeft" id="section-a.1-7">
<pre>
Raw: :dan!user@host PRIVMSG #ircv3 :\x01ACTION \x01
Raw: :dan!user@host PRIVMSG #ircv3 :\x01ACTION\x01
Raw: :dan!user@host PRIVMSG #ircv3 :\x01ACTION
Formatted: * dan
</pre><a href="#section-a.1-7" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="clientinfo">
<section id="section-a.2">
<h2 id="name-clientinfo">
<a href="#section-a.2" class="section-number selfRef">A.2. </a><a href="#name-clientinfo" class="section-name selfRef">CLIENTINFO</a>
</h2>
<div class="artwork art-text alignLeft" id="section-a.2-1">
<pre>
Query: CLIENTINFO
Reply: CLIENTINFO <tokens>
</pre><a href="#section-a.2-1" class="pilcrow">¶</a>
</div>
<p id="section-a.2-2">Clients which implement this message MUST reply with a list of the CTCP messages they support, delimited by an ASCII space. Some legacy implementations add an extra text message at the end prefixed by a colon, as demonstrated in the examples.<a href="#section-a.2-2" class="pilcrow">¶</a></p>
<p id="section-a.2-3">CLIENTINFO is widely implemented. Clients SHOULD implement this CTCP message.<a href="#section-a.2-3" class="pilcrow">¶</a></p>
<p id="section-a.2-4">Example:<a href="#section-a.2-4" class="pilcrow">¶</a></p>
<div class="artwork art-text alignLeft" id="section-a.2-5">
<pre>
Query: CLIENTINFO
Reply: CLIENTINFO ACTION DCC CLIENTINFO PING TIME VERSION
</pre><a href="#section-a.2-5" class="pilcrow">¶</a>
</div>
<div class="artwork art-text alignLeft" id="section-a.2-6">
<pre>
Query: CLIENTINFO
Reply: CLIENTINFO CLIENTINFO PING VERSION :Use CLIENTINFO
<COMMAND> to get more specific information
</pre><a href="#section-a.2-6" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="dcc">
<section id="section-a.3">
<h2 id="name-dcc">
<a href="#section-a.3" class="section-number selfRef">A.3. </a><a href="#name-dcc" class="section-name selfRef">DCC</a>
</h2>
<div class="artwork art-text alignLeft" id="section-a.3-1">
<pre>
Query: DCC <type> <argument> <host> <port>
Reply: Described elsewhere.
</pre><a href="#section-a.3-1" class="pilcrow">¶</a>
</div>
<p id="section-a.3-2">This message sets up connections that go directly between clients, bypassing the IRC server. This is typically used for features that require a large amount of traffic (e.g. file transfers), or simply direct chat that bypasses the server.<a href="#section-a.3-2" class="pilcrow">¶</a></p>
<p id="section-a.3-3">The Direct Client-to-Client (DCC) protocol requires its own specification, and is not described in-depth here.<a href="#section-a.3-3" class="pilcrow">¶</a></p>
<p id="section-a.3-4">DCC is widely implemented. Clients MAY implement this CTCP message.<a href="#section-a.3-4" class="pilcrow">¶</a></p>
</section>
</div>
<div id="finger">
<section id="section-a.4">
<h2 id="name-finger">
<a href="#section-a.4" class="section-number selfRef">A.4. </a><a href="#name-finger" class="section-name selfRef">FINGER</a>
</h2>
<div class="artwork art-text alignLeft" id="section-a.4-1">
<pre>
Query: FINGER
Reply: FINGER <info>
</pre><a href="#section-a.4-1" class="pilcrow">¶</a>
</div>
<p id="section-a.4-2">Clients which implement this message MUST reply with miscellaneous information about the user (typically the contents of their realname/gecos field). However, some implementations return the client name and version instead.<a href="#section-a.4-2" class="pilcrow">¶</a></p>
<p id="section-a.4-3">FINGER is largely obsolete. Clients MAY implement this CTCP message.<a href="#section-a.4-3" class="pilcrow">¶</a></p>
<p id="section-a.4-4">Example:<a href="#section-a.4-4" class="pilcrow">¶</a></p>
<div class="artwork art-text alignLeft" id="section-a.4-5">
<pre>
Query: FINGER
Reply: FINGER WeeChat 1.8-dev
</pre><a href="#section-a.4-5" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="ping">
<section id="section-a.5">
<h2 id="name-ping">
<a href="#section-a.5" class="section-number selfRef">A.5. </a><a href="#name-ping" class="section-name selfRef">PING</a>
</h2>
<div class="artwork art-text alignLeft" id="section-a.5-1">
<pre>
Query: PING <info>
Reply: PING <info>
</pre><a href="#section-a.5-1" class="pilcrow">¶</a>
</div>
<p id="section-a.5-2">Clients which implement this message MUST send a reply containing exactly the same params as the original query. However, leading spaces MAY be stripped. This message confirms reachability and latency between two clients.<a href="#section-a.5-2" class="pilcrow">¶</a></p>
<p id="section-a.5-3">PING is universally implemented. Clients SHOULD implement this CTCP message.<a href="#section-a.5-3" class="pilcrow">¶</a></p>
<p id="section-a.5-4">Example:<a href="#section-a.5-4" class="pilcrow">¶</a></p>
<div class="artwork art-text alignLeft" id="section-a.5-5">
<pre>
Query: PING 1473523721 662865
Reply: PING 1473523721 662865
Query: PING foo bar baz
Reply: PING foo bar baz
</pre><a href="#section-a.5-5" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="source">
<section id="section-a.6">
<h2 id="name-source">
<a href="#section-a.6" class="section-number selfRef">A.6. </a><a href="#name-source" class="section-name selfRef">SOURCE</a>
</h2>
<div class="artwork art-text alignLeft" id="section-a.6-1">
<pre>
Query: SOURCE
Reply: SOURCE <info>
</pre><a href="#section-a.6-1" class="pilcrow">¶</a>
</div>
<p id="section-a.6-2">Clients which implement this message MUST reply with a URL where the source code for the client can be found.<a href="#section-a.6-2" class="pilcrow">¶</a></p>
<p id="section-a.6-3">SOURCE is rarely implemented. Clients MAY implement this CTCP message.<a href="#section-a.6-3" class="pilcrow">¶</a></p>
<p id="section-a.6-4">Example:<a href="#section-a.6-4" class="pilcrow">¶</a></p>
<div class="artwork art-text alignLeft" id="section-a.6-5">
<pre>
Query: SOURCE
Reply: SOURCE https://weechat.org/download
</pre><a href="#section-a.6-5" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="time">
<section id="section-a.7">
<h2 id="name-time">
<a href="#section-a.7" class="section-number selfRef">A.7. </a><a href="#name-time" class="section-name selfRef">TIME</a>
</h2>
<div class="artwork art-text alignLeft" id="section-a.7-1">
<pre>
Query: TIME
Reply: TIME <timestring>
</pre><a href="#section-a.7-1" class="pilcrow">¶</a>
</div>
<p id="section-a.7-2">Clients which implement this message MUST reply with the client's local time in a human-readable format. In practice, both the format returned by ctime() and the format described in Section 3.3 of <span>[<a href="#RFC5322" class="xref">RFC5322</a>]</span> are common. Earlier specifications recommended prefixing the time string with a colon, but this is no longer recommended.<a href="#section-a.7-2" class="pilcrow">¶</a></p>
<p id="section-a.7-3">Clients MAY default to UTC time for privacy reasons and only respond with the local time if the user enables it.<a href="#section-a.7-3" class="pilcrow">¶</a></p>
<p id="section-a.7-4">TIME is almost universally implemented. Clients MAY implement this CTCP message.<a href="#section-a.7-4" class="pilcrow">¶</a></p>
<p id="section-a.7-5">Example:<a href="#section-a.7-5" class="pilcrow">¶</a></p>
<div class="artwork art-text alignLeft" id="section-a.7-6">
<pre>
Query: TIME
Reply: TIME Mon, 08 May 2017 09:15:29 GMT
</pre><a href="#section-a.7-6" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="version">
<section id="section-a.8">
<h2 id="name-version">
<a href="#section-a.8" class="section-number selfRef">A.8. </a><a href="#name-version" class="section-name selfRef">VERSION</a>
</h2>
<div class="artwork art-text alignLeft" id="section-a.8-1">
<pre>
Query: VERSION
Reply: VERSION <verstring>
</pre><a href="#section-a.8-1" class="pilcrow">¶</a>
</div>
<p id="section-a.8-2">Clients which implement this message MUST reply with the name and version of the client software in use. There is no specified format for the version string.<a href="#section-a.8-2" class="pilcrow">¶</a></p>
<p id="section-a.8-3">Clients MAY receive more than one reply after sending a VERSION query. Clients may allow users to customise the response value for this query.<a href="#section-a.8-3" class="pilcrow">¶</a></p>
<p id="section-a.8-4">VERSION is universally implemented. Clients SHOULD implement this CTCP message.<a href="#section-a.8-4" class="pilcrow">¶</a></p>
<p id="section-a.8-5">Example:<a href="#section-a.8-5" class="pilcrow">¶</a></p>
<div class="artwork art-text alignLeft" id="section-a.8-6">
<pre>
Query: VERSION
Reply: VERSION WeeChat 1.8-dev (git: v1.7-329-g22f2fd03a)
</pre><a href="#section-a.8-6" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="userinfo">
<section id="section-a.9">
<h2 id="name-userinfo">
<a href="#section-a.9" class="section-number selfRef">A.9. </a><a href="#name-userinfo" class="section-name selfRef">USERINFO</a>
</h2>
<div class="artwork art-text alignLeft" id="section-a.9-1">
<pre>
Query: USERINFO
Reply: USERINFO <info>
</pre><a href="#section-a.9-1" class="pilcrow">¶</a>
</div>
<p id="section-a.9-2">Clients which implement this message MUST reply with miscellaneous information about the user (typically the contents of their realname/gecos field).<a href="#section-a.9-2" class="pilcrow">¶</a></p>
<p id="section-a.9-3">USERINFO is largely obsolete. Clients MAY implement this CTCP message.<a href="#section-a.9-3" class="pilcrow">¶</a></p>
<p id="section-a.9-4">Example:<a href="#section-a.9-4" class="pilcrow">¶</a></p>
<div class="artwork art-text alignLeft" id="section-a.9-5">
<pre>
Query: USERINFO
Reply: USERINFO fred (Fred Foobar)
</pre><a href="#section-a.9-5" class="pilcrow">¶</a>
</div>
</section>
</div>
</section>
</div>
<div id="change-history-rfc-editor-please-remove-this-section">
<section id="section-appendix.b">
<h2 id="name-change-history-rfc-editor-p">
<a href="#section-appendix.b" class="section-number selfRef">Appendix B. </a><a href="#name-change-history-rfc-editor-p" class="section-name selfRef">Change History [RFC Editor: Please remove this section]</a>
</h2>
<p id="section-appendix.b-1">Changes from draft 2 (... 2021)<a href="#section-appendix.b-1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-appendix.b-2.1">Removed the CTCP Types section (thanks James).<a href="#section-appendix.b-2.1" class="pilcrow">¶</a>
</li>
<li class="normal" id="section-appendix.b-2.2">Added advice on leading spaces in messages (thanks Sadie).<a href="#section-appendix.b-2.2" class="pilcrow">¶</a>
</li>
<li class="normal" id="section-appendix.b-2.3">Minor ABNF fix.<a href="#section-appendix.b-2.3" class="pilcrow">¶</a>
</li>
</ul>
<p id="section-appendix.b-3">Changes from draft 1 (July 18, 2017)<a href="#section-appendix.b-3" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-appendix.b-4.1">General editing, fixed mistypes.<a href="#section-appendix.b-4.1" class="pilcrow">¶</a>
</li>
<li class="normal" id="section-appendix.b-4.2">Simplified some of the examples.<a href="#section-appendix.b-4.2" class="pilcrow">¶</a>
</li>
</ul>
<p id="section-appendix.b-5">Changes from draft 0 (May 29, 2017)<a href="#section-appendix.b-5" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-appendix.b-6.1">Added note about servers truncating CTCP messages (thanks Sadie).<a href="#section-appendix.b-6.1" class="pilcrow">¶</a>
</li>
<li class="normal" id="section-appendix.b-6.2">Fixed misspellings and added note to TIME about previously-recommended prefix (thanks Patrick).<a href="#section-appendix.b-6.2" class="pilcrow">¶</a>
</li>
<li class="normal" id="section-appendix.b-6.3">Mentioned how to parse/send empty ACTION messages (thanks dequis and the crew).<a href="#section-appendix.b-6.3" class="pilcrow">¶</a>
</li>
</ul>
</section>
</div>
<div id="authors-addresses">
<section id="section-appendix.c">
<h2 id="name-authors-addresses">
<a href="#name-authors-addresses" class="section-name selfRef">Authors' Addresses</a>
</h2>
<address class="vcard">
<div dir="auto" class="left"><span class="fn nameRole">Mantas Mikulėnas</span></div>
<div dir="auto" class="left"><span class="org">Independent</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:grawity@gmail.com" class="email">grawity@gmail.com</a>
</div>
</address>
<address class="vcard">
<div dir="auto" class="left"><span class="fn nameRole">Daniel Oakley (<span class="role">editor</span>)</span></div>
<div dir="auto" class="left"><span class="org">ircdocs</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:daniel@danieloaks.net" class="email">daniel@danieloaks.net</a>
</div>
</address>
</section>
</div>
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