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

Vikram Ragukumar vragukumar at signalogic.com
Tue Jan 18 20:27:50 CET 2011


Alex, Klaus thank you for your replies.

> 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.

Yes, the softphones are registered to the SIP server, and hence the SIP 
server has the IP:port information required to contact the softphone. 
However, the SIP server does not include the port number in the R-URI of 
the INVITE that it generates.

This port number is dynamically assigned by the firewall and is not 
fixed, so manipulating the pseudo variable $rp by assigning it a fixed 
number will not work.

If it is not mandatory to include the port number in the R-URI, how does 
the proxy determine the port to which the SIP message must be forwarded ?

Thanks and Regards,

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