Hi Jo, Thanks for the response. How about if I do the same thing, except send a CANCEL this time. Since CANCEL's are always responded to with a 200 it would also be multicast back to me. Would this work? (or if the outbound proxy was stateless I guess it wouldn't respond to the CANCEL request :/ ) I was just trying to find an alternate way to the DHCP / DNS SRV lookup mechanism in environments where you may need to use an outbound proxy (to traverse a firewall) which does not have any SIP SRV records, and the SIP proxy server is not running on the address of the domain. I suppose this environment may be one of the corner cases and the answer would be to upgrade the DNS server and add an SRV record. Anyone think this may be a more prevalent case and need considering? or have I wandered off in the woods again? Thanks, -Jeff From: Jo Hornsby [mailto:[EMAIL PROTECTED]] > > From: Jeff Mark [mailto:[EMAIL PROTECTED]] > > > > [...] > > > > Consider the following: if I multicast an INVITE request with > > Max-Forwards: 0 and then wait for the proxies listening on the > > multicast address to respond with 483 Too Many Hops. The UAC > > could use the address the 483 came from as the value of the > > outbound proxy and unicast future requests through this proxy. > > Would this be another valid approach to finding an outbound > > proxy? Any thoughts? > > Unfortunately this won't work, since servers are not supposed > to respond to multicast requests with anything other than 2xx > or 6xxs. [10.1 of bis02] (Well, it turns out that there are > actually some 4xx that a server can return, but 483 is not one > of them. > > HTH, > > > - Jo. _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
