Iñaki Baz Castillo writes:
Maybe OpenSer tries first with TCP (since the incoming INVITE uses TCP) and if it can't establish a connection then it tries UDP? Is it RFC 3261 mandatory?
inaki,
how to select ip/port/transport of next hop is described in
J. Rosenberg and H. Schulzrinne, ÈSession initiation protocol (SIP): locating SIP servers,É RFC 3263, Internet Engineering Task Force, June 2002.
-- juha