On Jul 08, 2009 at 10:58, Klaus Darilion klaus.mailinglists@pernau.at wrote:
Thanks!
Just for clarification:
dns
This parameter controls if the SIP server will try doing a DNS lookup on the address in the Via header of a received sip request to decide if adding a received=<src_ip> parameter to the Via is necessary. Note that Vias containing DNS names (instead of IPs) should have received= added, so turning dns to yes is not recommended.
Default is no.
Does this mean that, if the Via header in the received message contains a domain and:
dns=yes, a lookup is done, and if the domain resolves to the src_ip, then the "received" parameter is not added, but only added when the domain resolves to a different IP address?
Yes.
dns=no: the "received" parameter is always added?
Yes, if the address in Via is a DNS name and not an IP (and this is the recommended behaviour according to the rfc).
What about the behavior when the Via header contains an IP address (does this parameter affects the behavior)? Is the "received" parameter always added, or only if it Via-IP differs from source-IP? What about existing "received" parameter - will they be deleted/overwritten.
If the Via contains an IP, received is only added if the Via-IP!=src_IP.
I ask because some time ago we had problems in Kamailio.
I think they do exactly the same thing in kamailio. These config params. are very old, from the early days of ser and I doubt anyone touched them. BTW: they can be turned on from the command line (-r and -R).
Andrei