Network Working Group B. Fenner Internet-Draft AT&T Labs - Research Updates: 2782 (if approved) June 21, 2005 Expires: December 23, 2005 An IANA Registry for DNS SRV service names draft-fenner-iana-dns-srv-00 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on December 23, 2005. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This document proposes a registry for service names used in DNS SRV records. 1. Introduction The traditional interpretation of the service name used in SRV records [RFC2782] is that the name from the port number registry [[anchor2: is this the Fenner Expires December 23, 2005 [Page 1] Internet-Draft IANA for DNS SRV June 2005 best way to refer to this? urn:iana:port-numbers? "The IANA Port Number registry"? --wcf]] is used as the name of the service. However, one of the possible uses for SRV records is to avoid the need for a unique port number, by having the port number specified in the DNS record. The use of the port-numbers repository requires assignment of a port number along with the name. One community resource that has sprung up to address this problem is . There may, of course, be others, and of course registration in this registry doesn't prevent the same name being used for a port number, or being registered in a different community registry, etc. This document proposes the use of a registry that consists only of service names, with no associated port numbers, and describes procedures for maintaining this registry. 2. Registry for Service Names The service name registry was originally established for the names of services as used in WKS records. Since [RFC2782] only refers to "as defined in Assigned Numbers", which contains both of these registries, it's not clear which registry is meant. Since this registry contains only service names and descriptions, it's a better match to the requirements of SRV records. This document proposes moving to this registry, with a plan for transition and rules for maintenance of the new registry. 3. Transition All service names in the port-numbers registry will be copied to the service-names registry, along with their descriptions and any available references. Ad-hoc registries such as should be copied too; readers are requested to notify the author if they know of any other ad-hoc registries; IANA will be asked to copy from the list of ad-hoc registries that exist in this document at the time of publication. 4. Future Registrations In order to point to the correct registry, RFC 2782 is modified to read: Service The symbolic name of the desired service, as defined in [[anchor5: urn:iana:service-names ? "The IANA Service Names registry"? --wcf]] or locally. An underscore (_) is prepended to the service identifier to avoid collisions Fenner Expires December 23, 2005 [Page 2] Internet-Draft IANA for DNS SRV June 2005 with DNS labels that occur in nature. Any future registries in the port-numbers registry will be mirrored in the service-names registry. The protocol name space is shared between the port-numbers and service-names registry; new registrations in the port-numbers registry must not be allowed to overlap with a name in the service-names registry (unless they are the same protocol). 5. IANA Considerations New registrations in the service-names registry should be assigned on a First Come First Served basis as defined in [RFC2434]. The information required is a service name, description, and reference to the protocol specification or any additional information. The protocol specification may be referred to by RFC number or URL, and is optional. As in the port number registry, the service name is limited to 14 characters, composed of letters, digits and hyphens. The service name is not case-sensitive and is normally registered in all lowercase.[[anchor6: Are these the right restrictions on the character set and/or length of service names? --wcf]][[anchor7: 14 chars, letters-digits-hyphens just like port names --marc]][[anchor8: 63 octets dns label limit --olaf]] New registrations in the port-numbers registry will automatically be added to the service-names registry as well. A registration in the service-names registry that requires a port number in the future may be registered using the normal port-numbers procedure. As described in Section 3, IANA is asked to copy into the service- names registry existing registrations from the port number registry and the following ad-hoc community registries: o o (...any others that are identified before RFC publication) 6. Security Considerations Having a single registry for SRV service names eliminates the confusion caused by duplicate service names, where a client could look up one service and get a different service that uses the same name. 7. Acknowledgements This proposal first floated on the namedroppers list in May, 2004. Paul Vixie, Marc Krochmal, Stuart Cheshire and Olaf Kolkman provided Fenner Expires December 23, 2005 [Page 3] Internet-Draft IANA for DNS SRV June 2005 valuable feedback on earlier versions of this draft. 8. Normative References [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. [RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for specifying the location of services (DNS SRV)", RFC 2782, February 2000. Author's Address Bill Fenner AT&T Labs - Research 75 Willow Rd Menlo Park, CA 94025 USA Phone: +1 650 330-7893 Email: fenner@research.att.com Appendix A. Contents of new service-names registry This is the proposed contents of the service-names registry. (note: the contents of ad-hoc registries have not yet been incorporated) [[anchor11: This hasn't been checked against the current contents of the service-names for duplicates. I originally included this in the file, but since it made the I-D 98 pages long, I moved it: --wcf]] Fenner Expires December 23, 2005 [Page 4] Internet-Draft IANA for DNS SRV June 2005 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2005). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Fenner Expires December 23, 2005 [Page 5]