Internet-Draft Ryan Moats draft-ietf-svrloc-discovery-00.txt AT&T Expires in six months Martin Hamilton Loughborough University February 1997 Finding Stuff (How to discover services) Filename: draft-ietf-svrloc-discovery-00.txt Status of This Memo This document is an Internet-Draft. 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.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet- Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). Abstract This document proposes a solution to the problem of finding information about that services are being offered at a particular Internet domain. Therefore, it is possible for clients, using this approach, to located services in a domain with only prior knowledge of the domain name. 1. Rationale Currently, there is no one single way of discovering the network services and application protocols supported at a particular Internet domain. The Domain Name System (DNS - [1,2]) provides some basic facilities for finding the hosts that offer particular services, such as DNS servers themselves (NS records), and mail exchangers (MX records). However, neither mechanisms for locating arbitrary servers Expires 8/31/97 [Page 1] INTERNET DRAFT Finding Stuff February 1997 of arbitrary protocols nor search capabilities are provided. By following the simple process proposed here, this lack can be avoided. 2. The process Once a domain name has been determined, clients that want to locate services in that domain should follow the following three step process: 1. Look for SRV records (see [1]) in DNS associated with a service. 2. Look for common aliases (see [2]) in DNS. 3. Look for "service:" URLs in DNS. (see [3] and [4]). If a DNS lookup in steps 1 and 2 provides "service:" URL information as "Additional Information," then step 3 may be skipped. 3. Security Considerations There are no additional security considerations beyond those naturally inherent in the DNS introduced by this draft. 4. Conclusion By following the above process, a client may be reasonably certain of determining whether a particular service is provided for a particular domain name, given the domain name. 5. Acknowledgments This document is partially supported by the National Science Foundation, Cooperative Agreement NCR-9218179, the UK Electronic Libraries Programme (eLib) grant 12/39/01, and the European Commission's Telematics for Research Programme grant RE 1004. 6. References Request For Comments (RFC) and Internet Draft documents are available from and numerous mirror sites. [1] A. Gulbrandsen, P. Vixie, "A DNS RR for specifying the location of services (DNS SRV)," RFC 2052, October 1996. [2] M. Hamilton, R. Wright, "Use of DNS Aliases for Network Services," Internet Draft (work in pro- gress), June 1996. Expires 8/31/97 [Page 2] INTERNET DRAFT Finding Stuff February 1997 [3] R. Moats, M. Hamilton, "Advertising Services," Internet Draft (work in progress), February 1997. [4] E. Guttman, "The service: URL Scheme," Internet Draft (work in progress), November 1996. 7. Authors' addresses Ryan Moats AT&T 15621 Drexel Circle Omaha, NE 68135-2358 USA Phone: +1 402 894-9456 EMail: jayhawk@ds.internic.net Martin Hamilton Department of Computer Studies Loughborough University of Technology Leics. LE11 3TU, UK Email: m.t.hamilton@lut.ac.uk This Internet Draft expires May 19, 1997. Expires 8/31/97 [Page 3]