Subject: Receiver-tagged Via

From: Shail Bhatnagar <[email-masked]>
Date: Tue, 14 Mar 2000 18:10:41 -0500

Can a stateful proxy simply save the upstream addr (for request) and port
number of topmost Via it receives and not worry about resolving the Via header
in the response ?? Then there is no need to append the received parameter to
the Via of the previous hop.
I understand that the mechanism allows stateless proxy to route the response
correctly.

Comments ??
-- 
Best regards,
Shail

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From: Igor Slepchin <[email-masked]>
Date: Tue, 14 Mar 2000 18:36:48 -0500

> the Via of the previous hop.

I think it's OK to use the saved information if you still remember the
transaction state when response is received. However, you still need to
be prepared to process Via headers for responses for which there is no
such state info, e.g., because the corresponding transaction state was
destroyed due to a timeout or even because the proxy was rebooted. The
implication is that you certainly need to add the received tag if the
source IP address does not match that in the topmost Via. 

Also, note that _only_ the source IP address should be used, _NOT_ the
port; the port should be taken from the Via (or assumed to be 5060 if
none is present).

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Igor Slepchin