[OpenSIPS-Users] 302 redirect problem

[Nauman Sulaiman]

Hi , we have a set up where we are using a SIP proxy( OpenSIPS) to handle a 302 redirect locally but it doesn't seem to be working with voip providers here is the call flow. Is it legal, if so we'll bother you with a SIP trace. The 302 is handled locally by the OpenSIPS proxy and generates a new call leg but can't establish a dialog with Sipgate or Voipfone

                 INVITE             INVITE
VoipFone Server ---------> Proxy ------------> UAC1
                  Trying
VoipFone  Server <--------  Proxy
                                    180 Ring
                 180 Ring       <------------- UAC1
                <------    Proxy    302 Redir
                                <-------------- UAC1
                                    INVITE
                                ---------------> UAC2
                                   180 Ring
                                <----------------UAC2
                  180 Ring
VoipFone Server <----------   
                  CANCEL     
               ------------>         200 OK
                 200 OK         <--------------- UAC2
               <------------

THe VoipFone server sends a cancel straight after the 180 ring, Sipgate
doesn't do this however it never sends an ACK for the 200K, anyway both
don't like what we are doing.

We need to do the 302 redirect locally on our proxy as not all Voip providers support it so we can't let it go all the way back. Hope its clear what we are trying to, and is there any way forward.

Here is the code in our opensips.cfg file 

failure_route[1] {
        if (t_was_cancelled()) {
                exit;
        }

        get_redirects("3:1");
        t_relay();
}

Thanks