Pierre-Luc Bacon schrieb: > > Now, does the RFC say to do so ? Unfortunately yes. RFC 3263: > The procedures here MUST be done exactly once per transaction, where > transaction is as defined in [1]. That is, once a SIP server has > successfully been contacted (success is defined below), all > retransmissions of the SIP request and the ACK for non-2xx SIP > responses to INVITE MUST be sent to the same host. Furthermore, a > CANCEL for a particular SIP request MUST be sent to the same SIP > server that the SIP request was delivered to. From a practical point of view this is bad (as you experienced), because if there is a dialog stateful element (e.g. SBC, IP-PBX), the in-dialog requests will be rejected and nonces wont be accepted. Thus, IMO the client should send all messages which belong together (re-registrations, in-dialog requests) to the same IP address (usually the one which was resolved during initial registration). Only if there is a problem, the domain should be resolved again and a new IP should be choosen. regards klaus
