[sr-dev] dns= and rev_dns= parameter

[Klaus Darilion]

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?

dns=no: the "received" parameter is always added?

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.

I ask because some time ago we had problems in Kamailio.

regards
klaus

Andrei Pelinescu-Onciul schrieb:
> On Jul 06, 2009 at 19:36, Klaus Darilion
> <klaus.mailinglists at pernau.at> wrote:
>> Hi!
>> 
>> Can someone please review the documentation of the dns= and
>> rev_dns= parameter? 
>> http://sip-router.org/wiki/cookbooks/core-cookbook/devel#dns
>> 
>> They are more or less the same, and the described behavior has IMO
>>  nothing to do with the Via's received parameter.
>> 
>> Please also describe dns_cache_del_nonexp
> 
> Done, thanks!
> 
> Andrei