When our MGW sends an intial INVITE message to the ICSCF the ICSCF does not handle the call correctly. After analyzing the problem whe noticed that the reason for this is that the request URI of the INVITE contains a portnumber:

INVITE sip:01234@openims.org:5060 SIP/2.0


I believe that this request is conform the SIP specifications.

We added a rewriterule to the configuration of the ICSCF to temporarly fix this issue. We put this after the route sanity checks in the main routing logic:

if (uri =~ "sip:.+@openims.org:5060") {
log(1, "port found in request URI, rewriting...");
rewritehostport("openims.org");
}