[SIPForum-discussion] rport and received parameter in Via header

[Dale R. Worley]

Gnana Guru Natarajan <gnanaguru3012 at gmail.com> writes:
> What is the purpose of rport and received parameter in sip via
> header? Will it be needed if sip client is behind NAT router? If so, how
> router can process this sip header as router only handle the IP header but
> cannot application layer header?

The purpose of "rport" and "received" is to enable the receiver of a SIP
request to properly deal with requests that have passed through NATs.
In ordinary use, the NAT does *not* alter these prameters.

The details of their use are in RFCs 3261 and 3581.

Dale