[SR-Users] Re-invites from carrier breaks the call

Ovidiu Sas osas at voipembedded.com
Thu Feb 19 19:04:45 CET 2015


Well ... kamailio is a proxy (not a B2BUA), and in dialog requests should
not point at the proxy.
If you are paranoid about it, then you can alter signalling by mangling and
de-mangling the Contact header for requests and reply to achieve that.

Regards,
Ovidiu Sas

On Thu, Feb 19, 2015 at 12:59 PM, Andres <andres at telesip.net> wrote:

>  On 2/18/15 9:44 PM, Will Ferrer wrote:
>
> Hi Alex
>
>  Thanks so much for the reply.
>
>  Is there anything that we could do perhaps that is a more creative
> solution, for instance not passing the re-invite all the way to the
> softphone and just responding from the kamailio box handling the call?
>
>  We tried this as well actually, but we didn't get it to work. We just
> sent a 200 ok from the kamailio box, no sdp or anything on the packet since
> we sent it with just send_reply and the carrier just sent a bye.
>
>  Hopefully there is something clever we could do to correct the problem,
> it is preventing us from using alot of our carriers since the re-invite
> breaks our clients softphones.
>
>  Thanks again for the assistance.
>
> We have struggled with this issue ourselves.  The problem was that we did
> not want our SIP server to behave like an open relay.  We were seeing that
> the session-timer Re-Invites have a  Request-URI with the IP of the other
> endpoint instead of the Proxy.  If the SIP server is an open relay then no
> problem, but ours is not so the config file was very strict and dropped the
> Re-Invite (since the Request-URI had an external IP) thus dropping the
> call.  The config file could be enhanced by testing for has_totag() since
> the Re-Invite has the totag but an original Invite does not, but the hacker
> could put a bogus totag and make calls so its more secure to leave it this
> way.  We ended up disabling session-timers at some our clients PBXs.  Its
> always a balancing act between convenience/services and more security.  We
> chose more security.
>
>
>  All the best.
>
>  Will Ferrer
>
> On Wed, Feb 18, 2015 at 6:07 PM, Alex Balashov <abalashov at evaristesys.com>
> wrote:
>
>>  Kamailio cannot correct this. This is an endpoint issue. The whole
>> point of Record-Route is to hairpin sequential requests (and indeed, their
>> replies) through the proxy. The endpoints need to comply by affixing the
>> correct Route header to the end-to-end ACK.
>>
>>  --
>> Sent from my BlackBerry. Please excuse errors and brevity.
>>    *From: *Will Ferrer
>> *Sent: *Wednesday, February 18, 2015 9:01 PM
>> *To: *Kamailio (SER) - Users Mailing List
>> *Reply To: *Kamailio (SER) - Users Mailing List
>> *Subject: *[SR-Users] Re-invites from carrier breaks the call
>>
>>  Hi All
>>
>>  We have any issue with re invites coming from the carrier.
>>
>>  When a reinvite occurs, our softphone client gets the invite, sends a
>> 100, and then sends 200 ok. However the 200 ok does not have the softphones
>> ip in the record route. Since it's not in the record route the ack from the
>> carrier never makes it's way all the back to the softphone.
>>
>>  This causes the softphone to keep sending 200 oks since it never gets
>> the ack.
>>
>>  Eventually the softphone gets tired of sending 200 oks and sends a bye.
>>
>>  Is there any way that Kamailio can help me correct for this, or do we
>> need to have our clients use different softphones? If it has to be handled
>> via softphones is there even a softphone that can account for this?
>>
>>  Thanks for all your assistance in advance.
>>
>> All the best.
>>
>>  Will Ferrer
>>
>>  Switchsoft
>>
>>
>>
>>
>> _______________________________________________
>> SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
>> sr-users at lists.sip-router.org
>> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
>>
>>
>
>
> _______________________________________________
> SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing listsr-users at lists.sip-router.orghttp://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
>
>
>
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> Technical Supporthttp://www.cellroute.net
>
>
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VoIP Embedded, Inc.
http://www.voipembedded.com
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