Re: [OpenSER-Users] The Via Header of CANCEL Message

Hi Klaus: RFC 3665 page 54 line 4: A CANCEL constructed by a client MUST have only a single Via header field value matching the top Via value in the request being cancelled. and RFC 3665 at page 53: CANCEL is referred to as a "hop-by-hop" request, since it is responded to at each stateful proxy hop. and RFC 3665 at page 21: Client: A client is any network element that sends SIP requests and receives SIP responses. Clients may or may not interact directly with a human user. User agent clients and proxies are clients. So, for my opinion, the role of proxy in this case of RFC 3665 section 3.8 is a client when it sends CANCEL message to Bob. If I misunderstand any RFC meanings, please correct me. Thank you very much. Best Regards, Fangyu Ling > fancy wrote: > >> According to RFC 3665 section 3.8 and RFC 3261 section 9, >> there is only one via header in CANCEL message >> (message F11, F13 at page 72 of RFC 3665). >> > Hi! > > I could find it in RFC 3665, but not in 3261. Where exactly in RFC 3261 > is mentioned that the CANCEL has only 1 Via header? > > Further, the example has only one Via header - but I could not find any > definition if this is a MUST or not. > > >> How can I remove the 2nd via header? >> > You would have to modify tm module and change the code which generates > the CANCEL message. > > regards > klaus > >