Independent Submission R. Hartmann Request for Comments: 7194 August 2014 Updates: 1459 Category: Informational ISSN: 2070-1721 Default Port for Internet Relay Chat (IRC) via TLS/SSL Abstract This document describes the commonly accepted practice of listening on TCP port 6697 for incoming Internet Relay Chat (IRC) connections encrypted via TLS/SSL. Status of This Memo This document is not an Internet Standards Track specification; it is published for informational purposes. This is a contribution to the RFC Series, independently of any other RFC stream. The RFC Editor has chosen to publish this document at its discretion and makes no statement about its value for implementation or deployment. Documents approved for publication by the RFC Editor are not a candidate for any level of Internet Standard; see Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7194. Copyright Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Hartmann Informational [Page 1]
RFC 7194 Default Port for IRC via TLS/SSL August 2014 Table of Contents 1. Rationale .......................................................2 2. Technical Details ...............................................2 2.1. Connection Establishment ...................................2 2.2. Certificate Details ........................................3 2.2.1. Server Certificate ..................................3 2.2.2. Client Certificate ..................................3 3. Security Considerations .........................................3 4. IANA Considerations .............................................4 5. Normative References ............................................4 6. Informative References ..........................................4 7. Acknowledgements ................................................5 Appendix A. Supporting Data ........................................6 1. Rationale Although system port assignments exist for IRC traffic that is plain text (TCP/UDP port 194) or TLS/SSL encrypted (TCP/UDP port 994) [IANALIST], it is common practice amongst IRC networks not to use them for reasons of convenience and general availability on systems where no root access is granted or desired. IRC networks have defaulted to listening on TCP port 6667 for plain text connections for a considerable time now. This is covered by the IRCU assignment of TCP/UDP ports 6665-6669. Similar consensus has been reached within the IRC community about listening on TCP port 6697 for incoming IRC connections encrypted via TLS/SSL [RFC5246]. 2. Technical Details 2.1. Connection Establishment An IRC client connects to an IRC server. Immediately after that, a normal TLS/SSL handshake takes place. Once the TLS/SSL connection has been established, a normal IRC connection is established via the tunnel. Optionally, the IRC server may set a specific user mode (umode) for the client, marking it as using TLS/SSL. Again, optionally, an IRC server might offer the option to create channels in such a way that only clients connected via TLS/SSL may join. For details on how IRC works, see [RFC1459], [RFC2810], [RFC2811], [RFC2812], and [RFC2813]. Please note that IRC is extremely fragmented, and implementation details can vary wildly. Most implementations regard the latter RFCs as suggestions, not as binding. Hartmann Informational [Page 2]
RFC 7194 Default Port for IRC via TLS/SSL August 2014 2.2. Certificate Details 2.2.1. Server Certificate The IRC server's certificate should be issued by a commonly trusted certification authority (CA). The Common Name should match the Fully Qualified Domain Name (FQDN) of the IRC server or have appropriate wildcards, if applicable. The IRC client should verify the certificate. 2.2.2. Client Certificate If the client is using a certificate as well, it should be issued by a commonly trusted CA or a CA designated by the IRC network. The certificate's Common Name should match the main IRC nickname. If the network offers nick registration, this nick should be used. If the network offers grouped nicks, the main nick or account name should be used. If the network offers nick registration, the client certificate should be used to identify the user against the nick database. See [CERTFP] for a possible implementation. 3. Security Considerations The lack of a common, well-established listening port for IRC via TLS/SSL could lead to end users being unaware of their IRC network of choice supporting TLS/SSL. Thus, they might not use encryption even if they wanted to. It should be noted that this document merely describes client-to- server encryption. There are still other attack vectors like malicious administrators, compromised servers, insecure server-to- server communication, channels that do not enforce encryption for all channel members, malicious clients, or comprised client machines on which logs are stored. Those attacks can by their very nature not be addressed by client-to- server encryption. Additional safeguards are needed if a user fears any of the threats above. Hartmann Informational [Page 3]
RFC 7194 Default Port for IRC via TLS/SSL August 2014 This document does not address server links as there are no commonly accepted ports or even back-end protocols. Ports and back-end protocols are normally established in a bilateral agreement. All operators are encouraged to use strong encryption for back-end traffic, no matter if they offer IRC via TLS/SSL to end users. 4. IANA Considerations An assignment of TCP port 6697 for IRC via TLS/SSL has been made. The service name is "ircs-u" and the description "Internet Relay Chat via TLS/SSL": ircs-u 6697/tcp Internet Relay Chat via TLS/SSL 5. Normative References [RFC1459] Oikarinen, J. and D. Reed, "Internet Relay Chat Protocol", RFC 1459, May 1993. [RFC2810] Kalt, C., "Internet Relay Chat: Architecture", RFC 2810, April 2000. [RFC2811] Kalt, C., "Internet Relay Chat: Channel Management", RFC 2811, April 2000. [RFC2812] Kalt, C., "Internet Relay Chat: Client Protocol", RFC 2812, April 2000. [RFC2813] Kalt, C., "Internet Relay Chat: Server Protocol", RFC 2813, April 2000. [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, August 2008. 6. Informative References [IANALIST] IANA, "Service Name and Transport Protocol Port Number Registry", <http://www.iana.org/assignments/ service-names-port-numbers>. [TOP100] netsplit.de, "IRC Networks - Top 100", <http://irc.netsplit.de/networks/top100.php>. [MAVERICK] netsplit.de, "IRC Networks - in alphabetical order", <http://irc.netsplit.de/networks/ lists.php?query=maverick>. Hartmann Informational [Page 4]
RFC 7194 Default Port for IRC via TLS/SSL August 2014 [CERTFP] The Open and Free Technology Community, "OFTC - NickServ/CertFP", <http://www.oftc.net/oftc/NickServ/CertFP>. 7. Acknowledgements Thanks go to the IRC community at large for reaching a consensus. Special thanks go to the IRC operators who were eager to support port 6697 on their respective networks. Special thanks also go to Nevil Brownlee and James Schaad for working on this document in their capacities as Independent Submissions Editor and Reviewer, respectively. Hartmann Informational [Page 5]
RFC 7194 Default Port for IRC via TLS/SSL August 2014 Appendix A. Supporting Data As of October 2010, out of the top twenty IRC networks [TOP100] [MAVERICK], ten support TLS/SSL. Only one of those networks does not support TLS/SSL via port 6697 and has no plans to support it. All others supported it already or are supporting it since being contacted by the author. A more detailed analysis is available but does not fit within the scope of this document. Authors' Address Richard Hartmann Munich Germany EMail: richih.mailinglist@gmail.com URI: http://richardhartmann.de Hartmann Informational [Page 6]