Hi *,<br><br>What is the logic behind the transation matching in Kamailio. I am finding a problem whereby a call setup transaction (INVITE, 180 Ringing, PRACK, 200OK, ACK). between 2 Snom phones works in normal mode. However, when one phone is behind a NAT with STUN support, everything works perfectly (i.e. call setup, 2-way audio, etc), BUT the tm module doesnt match the transaction between the original invite and the subsequent messages (180, 200ok, etc). the impact here is that the fr_inv_timer eventually fires even though the call has been answered. Note: this only happens when the call is destined for the device behind the NAT.<br>
<br>Any ideas.<br><br>Perhaps an explanation on how the tm module does transaction manager.<br><br>RFC3261 states that transaction matching is done based on the via branch parameter.<br><br>Thanks in advance<br>Jason<br>