21 maj 2013 kl. 11:05 skrev ANAND KUMAR <[email protected]>: > Section 18.2.2 Sending Responses (For servers) of rfc3261 says: > > if the top Via has a "received" parameter, the response MUST be sent to the > address in the "received" parameter, using the port indicated in the > "sent-by" value, or using port 5060 if none is specified explicitly. If this > fails, for example, elicits an ICMP "port unreachable" response > > > Now assume a Client (which is behind a proxy and there may be a NAT between > the client and proxy) which is in a 2-way call receives BYE for this call (I > am assuming UAS behaviour by the Client) having top Via header with received > parameter (having ip address which is not same as that of the proxy). > > My query: > > 1. Then should this Client send 200 OK of BYE to this ip address (received)? Yes. > 2. Will this scenario ever happen for the client (also assume a NAT between > the Client and proxy for the purpose of analysis) in realtime? > 3. If this scenario will never happen in real time then does the RFC > statement(written above) stands valid for this Client (UAS in this case)? I don't understand these questions really. Sorry.
> > Please correct my understanding if it is wrong somewhere. > Do remember that the received header in the top via is added by the UA transaction layer, it's not received from the network. The UAS receiving the BYE message added the received parameter to remember the sender's real network address if it's different from the one given in the via: header read from the network. If there's aready a received parameter in the top most via header, it should not be trusted and hopefully the transaction layer will replace it with a correct one. Also, remember that the VIa could be a host name, not an IP address. In that case, your client propably needs to add a received header. /O _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
