RFC 2052 (rfc2052) - Page 1 of 10

A DNS RR for specifying the location of services (DNS SRV)

Alternative Format: Original Text Document
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Network Working Group                                     A. Gulbrandsen
Request for Comments: 2052                            Troll Technologies
Updates: 1035, 1183                                             P. Vixie
Category: Experimental                                 Vixie Enterprises
                                                            October 1996


       A DNS RR for specifying the location of services (DNS SRV)

Status of this Memo

   This memo defines an Experimental Protocol for the Internet
   community.  This memo does not specify an Internet standard of any
   kind.  Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

Abstract

   This document describes a DNS RR which specifies the location of the
   server(s) for a specific protocol and domain (like a more general
   form of MX).

Overview and rationale

   Currently, one must either know the exact address of a server to
   contact it, or broadcast a question.  This has led to, for example,
   ftp.whatever.com aliases, the SMTP-specific MX RR, and using MAC-
   level broadcasts to locate servers.

   The SRV RR allows administrators to use several servers for a single
   domain, to move services from host to host with little fuss, and to
   designate some hosts as primary servers for a service and others as
   backups.

   Clients ask for a specific service/protocol for a specific domain
   (the word domain is used here in the strict RFC 1034 sense), and get
   back the names of any available servers.

Introductory example

   When a SRV-cognizant web-browser wants to retrieve

      http://www.asdf.com/

   it does a lookup of

      http.tcp.www.asdf.com




Gulbrandsen & Vixie           Experimental
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