Hello all, I've been working on upgrading our SBC setup which consists of FreeSWITCH instances between Kamailio 3.1 instances. In initial testing FreeSWITCH would fail on an ACK timeout. After looking at the traces, Kamailio was responding to the 200 with an ACK that has a branch=0 parameter. It is possible to disable this behavior by setting syn_branch=0 in kamailio.cfg which causes an MD5 hash to be used as the branch parameter. In researching this it seems that this has been around in SER for some time as the ACK following the 200 is sent statelessly regardless of a t_relay() function. See: http://www.mail-archive.com/users@openser.org/msg00697.html The question I have is there any way to get Freeswitch to work with an ACK with a branch=0? and if so should it? Gotta love SIP. :-) Spencer