[SR-Users] ACK routing loop

[Daniel-Constantin Mierla]

Hello,

On 10/19/11 5:23 PM, Antanas Masevicius wrote:
> Hello,
>
> after troubleshooting ACK routing loops i came up with a thread:
> http://www.openser.org/pipermail/users/2009-March/004123.html
>
> In short, loops formed when i entered IP address to 'domain' table of a
> host which was remote.
> Call flow:
>
> UAC INVITE ->  Kamailio (with remote domain entered) ->  UAS (host whose
> IP matches that remote domain)
>
> It looks like after loose_route() check ACK to 200 OK gets routed to
> local host. Besides this issue, IP address of remote host in 'domain'
> table did no harm at all.
>
> Question is, is that normal ACK routing behaviour or loose_route()
> should still check if given IP in request is really bound to local
> interface?
domain module as well as aliases are ways of setting local domains even 
if they don't exist in DNS. Therefore practically you can have addresses 
like user at domainx.abc and domainx.abc not really existing. Thus, it is 
no intention of checking records in domain against dns and local network 
addresses.

When you add a domain to domain table, kamailio (via config file), will 
consider it as being for local routing.

> Domain module documentation states that "A “local” domain is one that
> the proxy is responsible for", but id does not tell you that you cannot
> set remote IP address as a local domain.

Well, when there is a foreign IP either there is a SIP application 
handling requests for it and you should let kamailio forward to it by 
not adding it to domain table, or there is no sip application and then 
kamailio will handle the requests locally since it is in the domain table.

Personally, I see no reason of why adding a remote IP to domain table, 
can you give some examples where it would be useful?

Cheers,
Daniel

-- 
Daniel-Constantin Mierla -- http://www.asipto.com
Kamailio Advanced Training, Dec 5-8, Berlin: http://asipto.com/u/kat
http://linkedin.com/in/miconda -- http://twitter.com/miconda