Hello,

I encounter unexpected behavior.

The call flow is:
UAC --> Kamailio + Rtpengine (full ipv4) --> Asterisk (full IPV4).

I configured the uac to use IPV4 but  the SIP INVITES include IPV6 in headers and sdp messages. I think this is a bug on the UAC side.

Example:

1. UAC INVITE

INVITE sip:xxx@sip.xxx.com SIP/2.0 Via: SIP/2.0/TLS [2a04:cec0:101a:ebe2:9949:d81c:23a6:ae10]:42580;branch=z9hG4bK.I8U1RQDbW;rport
.....
.....
v=0
o=59130c8f7268a_2 2922 1557 IN IP6 2a04:cec0:101a:ebe2:9949:d81c:23a6:ae10
s=Talk
c=IN IP6 2a04:cec0:101a:ebe2:9949:d81c:23a6:ae10

2. We sent 200 OK response like :

Via: SIP/2.0/TLS [2a04:cec0:101a:ebe2:9949:d81c:23a6:ae10]:42580;received=80.214.78.1;branch=z9hG4bK.I8U1RQDbW;rport=1364
v=0
o=x 887503534 887503534 IN IP4 51.159.2.164
s=x
c=IN IP4 51.159.2.164

3. We never receive the ACK message.

Is there a Kamailio or Rtpengine solution to solve the problem?

Any help will be very appreciate.