INTERNET-DRAFT S.Nyckelgard Expires: March 27, 2003 Telia Research AB September 27, 2002 DNS look-up for services related to a URI Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC 2026. 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. Copyright Notice Copyright (C) The Internet Society (2000). All Rights Reserved. Abstract This memo is an extension to ENUM RFC 2916 [3]. RFC 2916 describes how to utilize DNS as a look-up mechanism for services related to a telephone number. This memo describes how to utilize the same look- up mechanism for personal URIs (user@domain). Specifically, it defines how to translate personal URIs to DNS names. 1. Conventions used in this document 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 RFC 2119 [2]. S. Nyckelgard [Page 1] Internet Draft enum-uri September 2002 2. Introduction It is sometimes desirable to find out what services that are connected to a certain user identifier. ENUM RFC 2916 [3] defines how to utilize existing DNS services for the look-up but the range of user identifiers is limited to telephone numbers. This memo extends the scope to also incude personal URIs (user@domain). The look-up mechanism requires that the user identifier be translated to a DNS name. ENUM RFC 2916 [3] describes how to translate E.164 telephone numbers to DNS names. This memo describes how to translate personal URIs to DNS names. 3. The virtual "at" domain Internet domains that wish to use DNS as a repository for information regarding what services that are connected to their users MAY create a virtual sub-domain that serves as a kind of user directory in the DNS. The virtual sub-domain SHOULD be given the name "at". The name "at" derives from the rule for how to translate a personal URI to a DNS name. The rule is simple and intuitive: Replace the "@" sign found in personal URIs by the virtual domain name "at". Example: "john.doe@foo.com" translates to "john.doe.at.foo.com" A DNS query for "john.doe.at.foo.com" will return information related to the URI "john.doe@foo.com". URI-related information that can be stored by the DNS and the record structure for storing such information in the DNS are exactly the same as defined for telephone numbers by ENUM RFC 2916 [3]. See RFC 2916 for more information. Remark: The probability that an Internet domain has a non-virtual sub-domain named "at" that also happens to serve as a root for other sub-domains is extremely small. Having choosen a name other than "at" in order to reduce the risk of encountering a naming collision would hence not have counterbalanced the advantage of an intuitive naming convention. 4. Security Considerations The security considerations of ENUM RFC 2916 [3] apply here too. See RFC 2916 for more information. S. Nyckelgard [Page 2] Internet Draft enum-uri September 2002 5. References [1] Bradner, S., "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996. [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [3] Faltstrom, P., "E.164 number and DNS", RFC 2916, September 2000 6. Author's Address S÷ren Nyckelg…rd Telia Research AB Box 214 40123 Gothenburg Sweden soren.m.nyckelgard@telia.com +46 70 5732399 Full Copyright Statement Copyright (c) The Internet Society (2002). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of develop- ing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS 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. S. Nyckelgard [Page 3]