On Tue, 2008-12-02 at 16:53 -0500, Paul Kyzivat wrote: > As I read 3261, a proxy can't do this. The section on adding headers > from the URI to the message is in section 8, for UACs. In section 16, > for proxies, there is no comparable language. Instead, the proxy must > remove any parameters that aren't allowed in the R-URI, which would > include the headers. And it may indeed add additional headers, but I > believe it is restricted in doing so by Table 2. Table 2 doesn't permit > the proxy to add, modify, or delete an Expires header. > > Now this does seem a bit inconsistent. If a URI in a 3xx includes > headers, then they would apply if the 3xx is returned to the UAC, but > not apply if the 3xx is recursed by a proxy.
Interesting... People have discussed proxies for a long time as if they handled target URIs similarly to UASs generating initial requests, that is, header-parameter parts are extracted from the request-URI and turned into headers. Looking at RFC 3261 section 16.6 step 2, none of this is discussed. Step 5 says "The proxy MAY add any other appropriate header fields to the copy at this point." which seems to allow the proxy great latitude. Table 2 does forbid the proxy from modifying the Expires header. But perhaps that's an oversight? One could also argue that the proxy rules apply to UACs when they're recursing on 3xx responses, as they're "acting like proxies" then. Dale _______________________________________________ Sip mailing list https://www.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [EMAIL PROTECTED] for questions on current sip Use [EMAIL PROTECTED] for new developments on the application of sip
