183 Session Progress

Hi All,

I have to contact through a SIP trunk a device without SDP.
The device answers with a 180 ringing message followed by a 183 Session Progress (still without SDP)
Finally the device send a 487 Request Terminated.

As I found on the net, in case of a 183 Session Progress without SDP Asterisk replaces it by 180 Ringing.
My problem is that the device sends in the 183 Session Progress message a custom header which is required for my application.
It seems Asterisk doesn’t copy all headers from the origination message.

Which piece of code should I modify in the chan_sip.c file to modify the behavior?
I am not a C developer …

Thanks for your time.
Best regards

Asterisk is not a SIP proxy, it is a back to back user agent. Your requirement seems to require a SIP proxy.

Also, request terminated is generally the result of an explicit CANCEL.

This is not a support forum.

Thank you for your prompt answer.
I understood I have to abandon Asterisk.