This depends on how the UAC is configured. Many can be configured with an "outbound proxy" thru which all outbound requests are routed. Based on 3261 it seems that the preferred way for the UAC to implement the outbound proxy functionality is to preload requests with a Route header referencing the outbound proxy. In general there will be little intelligence in the UAC about this - it will simply insert the Route header in all new outbound requests. (Presumably those that aren't part of a dialog.)
It would be unwise to configure such a UAC with an outbound "proxy" that is in reality a server which always returns redirect responses. It clearly wouldn't work.
You could of course construct a UAC that knows about a redirect server, and knows how to use it. But it would require more complex logic in the UAC to do the right thing.
You can't simply expect a UAC that has an outbound proxy to bypass that proxy every time it gets a 3xx response. The 3xx may have come from further downstream, and the proxy may still be needed when retrying with the new address.
Paul
Bob Penfield wrote:
inline ----- Original Message ----- From: "Jonathan Rosenberg" <[EMAIL PROTECTED]>inline. Bob Penfield wrote:inline ----- Original Message ----- From: "Paul Kyzivat" <[EMAIL PROTECTED]><snip>If the client is treating the server as an outbound proxy, by using a preloaded Route header, why would it decide not to use the same preloaded route header when sending to the redirected address?You could certainly do that, but I if that server is just a redirectserverand not a proxy, there is no need to send the subsequent request backthruthe server.The UAC may not know that, though. Indeed, the spec does say that the Route headers would be present in the recursed request. From 8.1.3.4: > In all other respects, requests sent upon receipt of a redirect > response SHOULD re-use the header fields and bodies of the original > request. Local outbound redirect servers, IMHO, are a bad idea, because they can cause a ping-ponging effect.This does not seem right to me. The UAC has decided by some local policy to contact a given next-hop server and sends it a request. That server says, I can't do it, but so-and-so can by sending a redirect response. Why would the UAC then send the request back to the same server that just told it to go somewhere else? With the above rule, how would you ever not send it back to the redirect server? My understanding of 3261 is that unless you are sending the request to host indicated in the Request-URI, you put a Route header in.
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