[asterisk-users] On SIP INVITE answering to IP:port found in Contact: header.

[Markus]

Hi list!

I'm trying to get a DID routed to me and the provider seems to have an 
unusual setup. Or maybe not? From looking at their SIP header they are 
using "BroadWorks".

The problem: they're sending their SIP invite from port 36252. My 
Asterisk 10.7.1 is answering to that port 36252 but their BroadWorks 
thingie is not listening on that port, but instead on port 5060. So they 
want me to send my SIP responses to the IP:port they send via the 
Contact: header.

Here's the output from tcpdump (1.1.1.1 = them; 2.2.2.2 = me):

IP 1.1.1.1.36252 > 2.2.2.2.5060: UDP, length 845
[...]
Contact:<sip:1.1.1.1:5060>
[...]

My Asterisk' reply:

IP 2.2.2.2.5060 > 1.1.1.1.36252: UDP, length 602
[...]

I tried the following in the peer config in sip.conf:

host=1.1.1.1
type=peer
insecure=port,invite
port=5060

But that didn't change anything.

How can I tell Asterisk to honor and use the info found in Contact: when 
sending its replies?

Thank you!
Markus