[SR-Users] Detecting calls with missing ACK (Lazy SIP scanners)

[Marrold]

Hi,

>>On 06/04/16 01:57, Marrold wrote:
>> Hi Charles,
>>
>> I can confirm that t_any_timeout(), and t_branch_timeout() return true
>> when these un-ACKd transactions occur.

> by un-ACKed, do you mean they didn't receive any response or they didn't
> receive the ACK following a response to an INVITE?

I mean specifically the response to an INVITE was not ACK'd

>> I've been doing some experimentation with t_any_timeout()
and t_branch_timeout(), and I've observed they return true if either the
initial invite receives no response, or if the 200 OK >> is not
acknowledged by the UAC.
>> Is there any way of differentiating between these scenarios?

> If Kamailio matches the 200ok for transaction, then it should not give
true for a timeout check. But maybe there is a mismatch also in kamailio if
the 200ok is sent to caller but it is no > ACK sent back. In such case, a
sip network trace will be useful to investigate what happens there.

In this scenario a 200ok is sent to the caller, but no ACK is sent back.
This appears to return true for timeout checks. I will grab a SIP trace.

As a side note / update I figure I can potentially add a flag / AVP when a
response and / or ACK is received and figure out the cause of the timeout
from there.

Thanks for your assistance.



On Tue, Apr 12, 2016 at 7:57 AM, Daniel-Constantin Mierla <miconda at gmail.com
> wrote:

>
>
> On 10/04/16 21:57, Marrold wrote:
>
> I've been doing some experimentation with t_any_timeout()
> and t_branch_timeout(), and I've observed they return true if either the
> initial invite receives no response, or if the 200 OK is not acknowledged
> by the UAC.
>
> Is there any way of differentiating between these scenarios?
>
> If Kamailio matches the 200ok for transaction, then it should not give
> true for a timeout check. But maybe there is a mismatch also in kamailio if
> the 200ok is sent to caller but it is no ACK sent back. In such case, a sip
> network trace will be useful to investigate what happens there.
>
> Cheers,
> Daniel
>
> --
> Daniel-Constantin Mierlahttp://www.asipto.comhttp://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
> Kamailio World Conference, Berlin, May 18-20, 2016 - http://www.kamailioworld.com
>
>
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