currently i have a pbx pointing to our local sip trunk provider(it's also a SBC)
We register to them via x.x.x.x:5060.
I did a static port mapping from WAN_IP:5060 to LAN_PBX:5060 in order for signalling to come in.
Normal NAT is done.
With "ip nat service sip udp port 5060" (enable by default by the router)
--- FAIL INCOMING calls(not even ringing)
With "no ip nat service sip udp port 5060",an ethereal capture shows the source port of the SBC(of our sip provider) is 5075, instead of 5060.
-- Incoming ringing (but either no voice or 1 way audio)
anyone face such problem before?
i guess it's basically due to different signalling port i'm connecting to(port 5060) and return traffic (port 5075)