Force subsequent requests to be sent to source port of invite

[avayax]

@avayax

How do I determine if my server sends rport in the via header and which port it is?

I mean is there a setting for my chansip endpoint that lets me send or not send rport in the via header and set the port?

[avayax]

@avayax

So just to clarify, if I set nat=yes for my local chansip endpoint, that determines that my local server will ignore the IP and port information in the sip headers of an incoming invite and instead send responses to the source IP address/port of the IP packet.

@jcolp

Yes, that is correct.

With nat=yes, are RTP packets sent to the source IP address/port of the IP packet or to the IP/port information that’s in the SDP?

[jcolp]

“nat=yes” is an old way but it includes the “comedia” option, which is documented as such:

;   nat = comedia           ; Send media to the port Asterisk received it from regardless
;                           ; of where the SDP says to send it.

[avayax]

Send media only to the port Asterisk received it from or also to the IP address?

[jcolp]

Both. Sending it to only the port would be useless since it is likely the IP address would also be wrong in SDP.

[avayax]

So, with nat=yes, the information in the via and SDP headers of incoming invites is ignored, responses are sent to the IP/port of the packet, but subsequent requests are still sent to the IP/port that is in the contact header?

[jcolp]

No, with “nat=yes” all information provided in the SIP signaling is ignored and the actual source is used, including for subsequent requests.