[Serusers] ACK problem

[Hamish Archer]

Hi all,

I have ser operating with a combination of X-lite and grandstream 
phones. I am trying to get it it play nicely with Asterisk and have run 
into a strange situation. Calling from ser to asterisk works fine but 
when I try to call back from asterisk to ser I run into problems, the 
sip device (behind NAT)  rings but when I answer the call ser tries to 
send the ACK back to the private IP and not the public IP (found using 
STUN) that it was using up until that point.

I have the following debug from ngrep to illustrate the problem. 
Offending SIP packet marked with ########s

Any ideas?

#
U 222.152.11.236:36595 -> xx.xx.xx.52:5060
SIP/2.0 100 trying.
Via: SIP/2.0/UDP xx.xx.xx.52;branch=z9hG4bKbe2d.2a520d95.0.
Via: SIP/2.0/UDP xx.xx.xx.51:5080;branch=z9hG4bK6484622b.
From: "Hamish Archer" <sip:100 at xx.xx.xx.51:5080>;tag=as12db357a.
To: <sip:17778134000 at proxy02.blahblah.xxx>.
Call-ID: 1738a1ee3d2310af4082784e4d0a6d89 at xx.xx.xx.51.
CSeq: 102 INVITE.
User-Agent: Grandstream BT100 1.0.4.54.
Content-Length: 0.
.

#
U 222.152.11.236:36595 -> xx.xx.xx.52:5060
SIP/2.0 180 ringing.
Via: SIP/2.0/UDP xx.xx.xx.52;branch=z9hG4bKbe2d.2a520d95.0.
Via: SIP/2.0/UDP xx.xx.xx.51:5080;branch=z9hG4bK6484622b.
Record-Route: <sip:xx.xx.xx.52;ftag=as12db357a;lr=on>.
From: "Hamish Archer" <sip:100 at xx.xx.xx.51:5080>;tag=as12db357a.
To: <sip:17778134000 at proxy02.blahblah.xxx>;tag=760cdf6859149410.
Call-ID: 1738a1ee3d2310af4082784e4d0a6d89 at xx.xx.xx.51.
CSeq: 102 INVITE.
User-Agent: Grandstream BT100 1.0.4.54.
Content-Length: 0.
.

#
U 222.152.11.236:36595 -> xx.xx.xx.52:5060
SIP/2.0 180 ringing.
Via: SIP/2.0/UDP xx.xx.xx.52;branch=z9hG4bKbe2d.2a520d95.0.
Via: SIP/2.0/UDP xx.xx.xx.51:5080;branch=z9hG4bK6484622b.
Record-Route: <sip:xx.xx.xx.52;ftag=as12db357a;lr=on>.
From: "Hamish Archer" <sip:100 at xx.xx.xx.51:5080>;tag=as12db357a.
To: <sip:17778134000 at proxy02.blahblah.xxx>;tag=efb3a3fe9b832ccc.
Call-ID: 1738a1ee3d2310af4082784e4d0a6d89 at xx.xx.xx.51.
CSeq: 102 INVITE.
User-Agent: Grandstream BT100 1.0.4.54.
Content-Length: 0.
.

#
U 222.152.11.236:36595 -> xx.xx.xx.52:5060
SIP/2.0 200 OK.
Via: SIP/2.0/UDP xx.xx.xx.52;branch=z9hG4bKbe2d.2a520d95.0.
Via: SIP/2.0/UDP xx.xx.xx.51:5080;branch=z9hG4bK6484622b.
Record-Route: <sip:xx.xx.xx.52;ftag=as12db357a;lr=on>.
From: "Hamish Archer" <sip:100 at xx.xx.xx.51:5080>;tag=as12db357a.
To: <sip:17778134000 at proxy02.blahblah.xxx>;tag=760cdf6859149410.
Call-ID: 1738a1ee3d2310af4082784e4d0a6d89 at xx.xx.xx.51.
CSeq: 102 INVITE.
User-Agent: Grandstream BT100 1.0.4.54.
Contact: <sip:17778134000 at 192.168.1.158>.
Allow: INVITE,ACK,CANCEL,BYE,NOTIFY,REFER,OPTIONS,INFO,SUBSCRIBE.
Content-Type: application/sdp.
Content-Length: 209.
.
v=0.
o=17778134000 8000 8000 IN IP4 192.168.1.158.
s=SIP Call.
c=IN IP4 222.152.11.236.
t=0 0.
m=audio 5004 RTP/AVP 0 101.
a=rtpmap:0 PCMU/8000.
a=ptime:20.
a=rtpmap:101 telephone-event/8000.
a=fmtp:101 0-11.

#################################################
U xx.xx.xx.52:5060 -> 192.168.1.158:5060
ACK sip:17778134000 at 192.168.1.158 SIP/2.0.
Max-Forwards: 10.
Record-Route: <sip:xx.xx.xx.52;ftag=as12db357a;lr=on>.
Via: SIP/2.0/UDP xx.xx.xx.52;branch=0.
Via: SIP/2.0/UDP xx.xx.xx.51:5080;branch=z9hG4bK6484622b.
Route: <sip:17778134000 at 192.168.1.158>.
From: "Hamish Archer" <sip:100 at xx.xx.xx.51:5080>;tag=as12db357a.
To: <sip:17778134000 at proxy02.blahblah.xxx>;tag=760cdf6859149410.
Contact: <sip:100 at xx.xx.xx.51:5080>.
Call-ID: 1738a1ee3d2310af4082784e4d0a6d89 at xx.xx.xx.51.
CSeq: 102 ACK.
User-Agent: Asterisk PBX.
Content-Length: 0.
###################################################

#
U 222.152.11.236:36595 -> xx.xx.xx.52:5060
SIP/2.0 200 OK.
Via: SIP/2.0/UDP xx.xx.xx.52;branch=z9hG4bKbe2d.2a520d95.0.
Via: SIP/2.0/UDP xx.xx.xx.51:5080;branch=z9hG4bK6484622b.
Record-Route: <sip:xx.xx.xx.52;ftag=as12db357a;lr=on>.
From: "Hamish Archer" <sip:100 at xx.xx.xx.51:5080>;tag=as12db357a.
To: <sip:17778134000 at proxy02.blahblah.xxx>;tag=760cdf6859149410.
Call-ID: 1738a1ee3d2310af4082784e4d0a6d89 at xx.xx.xx.51.
CSeq: 102 INVITE.
User-Agent: Grandstream BT100 1.0.4.54.
Contact: <sip:17778134000 at 192.168.1.158>.
Allow: INVITE,ACK,CANCEL,BYE,NOTIFY,REFER,OPTIONS,INFO,SUBSCRIBE.
Content-Type: application/sdp.
Content-Length: 210.
.
v=0.
o=17778134000 8000 8000 IN IP4 192.168.1.158.
s=SIP Call.
c=IN IP4 222.152.11.236.
t=0 0.
m=audio 35337 RTP/AVP 0 101.
a=rtpmap:0 PCMU/8000.
a=ptime:20.
a=rtpmap:101 telephone-event/8000.
a=fmtp:101 0-11.