[SR-Users] Proxying INVITE message without port information in R-URI

[Klaus Darilion]

> When A places a call to B, an INVITE is proxied to the Sip Server from
> A. The Sip Server now sends another INVITE to the proxy, however the
> R-URI of this INVITE does not contain the port number that the INVITE is
> supposed to be sent to. Hence the proxy sends the INVITE to the default
> SIP port 5060. This port is not open in the firewall hence Softphone B
> never receives the INVITE.

Usually the softphones register to the proxy or SIP server. Thus, the 
proxy or SIP server knows under which IP:port (The IP:port from which 
the REGISTER was received) it can contact the sofpthone.

regards
klaus