Hi,

Does kamailio support PRACK method ? Any configuration change is needed?

It appears Kamailio does not like the PRAK when increasing Cseq.

Here is the call flow:

A send INVITE --> Kamailio --> proxy the packet to B

B send 180 Ringing --> Kamailio -> proxy the packet to A

A send PRAK (increase Cseq) --> Kamailio --> proxy the packet to B

B send 200 OK --> Kamailio -> proxy the packet to A

Kamailio re-send 180 Ringing to A

Thanks,