From: "Amit P. Ahuja" <[EMAIL PROTECTED]> Considering the behavior of UAS-2, my question is: whether any SIP standard suggests guidelines on whether it is advisable to send out responses from a UDP port which is different from the one on which the request was received? RFC 3261 - 18.2.2 Sending Responses only talks about the destination the response needs to be sent to, however nothing about the source.
The standard permits the sender to use any port of its choice. And in a "flat" network, the choice of port makes little difference. But as you note in another message, when NATs are present, it is difficult to make the SIP system work if you send responses from ports other than the one which received the request. (The sipX system used to use transient ports to send messages, but for these reasons we had to rebuild it to use "symmetric signaling", sending responses using the same port that receives requests.) Dale _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
