Yes for a response to an INVITE request. A Contact header is required for a 2xx response to a request that establishes a dialog (i.e. INVITE or SUBSCRIBE):
>From RFC 3261: 12.1.1 UAS behavior When a UAS responds to a request with a response that establishes a dialog (such as a 2xx to INVITE), the UAS MUST copy all Record-Route header field values from the request into the response (including the URIs, URI parameters, and any Record-Route header field parameters, whether they are known or unknown to the UAS) and MUST maintain the order of those values. The UAS MUST add a Contact header field to the response. The Contact header field contains an address where the UAS would like to be contacted for subsequent requests in the dialog (which includes the ACK for a 2xx response in the case of an INVITE). 13.3.1.4 The INVITE is Accepted The UAS core generates a 2xx response. This response establishes a dialog, and therefore follows the procedures of Section 12.1.1 in addition to those of Section 8.2.6. cheers, (-:bob Robert F. Penfield Chief Software Architect Acme Packet, Inc. 130 New Boston Street Woburn, MA 01801 [EMAIL PROTECTED] ----- Original Message ----- From: "sindhur" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, December 06, 2002 1:49 PM Subject: [Sip-implementors] contact header in 200 "OK" > Hi, > > Is a contact header mandatory in a 200 "OK" response? > > Sindhur. > > > _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
