[asterisk-dev] Bug or not - "no reply to our critical packet" ?

[samuel]

First of all check all network nodes (switches, routers,...) and check
whether the SIP signalling is OK in terms of NAT handling. Your problem is
that an ACK is lost and the session is torn down, this behaviour is OK.

If everything is OK, I would recommend that you use 1.4.18 because the NAT
handling is better. I've seen that from 1.4.18 there's a problem but I don't
know enough about the * internals to know where it is (i tried
1.4.20,1.4.22, 1.4.23)

The problem I've seen is the following:

How to detect with keep alive mechanism (easily to spot):

SIP endpoints behind a router without any ALG enabled and * in a public IP.

When SIP endpoints sends the keep alive (NOTIFY for example) the Via header
is a private one (192.168.1.1) and the source IP is the public interface of
the router.
Even though you have nat=yes in those endpoints, * returns the reply to the
private address (as stated by the RFCs) but it does not reach the endpoint
because the destination address is a private onte, instead of the IP where
the packet came from.


I know it's not RFC compliant but when I see this behaviour, some calls are
dropped with the "critical response" message because the ACK handling is
also not well done.

Hope anyone with enough knowledge can shed some light on this issue.

Best regards,
Samuel


2009/3/20 Serge Berney <s.berney at kinonline.net>

>  Hello everybody !
>
>
>
> Last day we experiment a communication drop with this error message :
>
>
>
> [Mar 18 12:35:27] WARNING[3854]: chan_sip.c:1958 retrans_pkt: Maximum
> retries exceeded on transmission
> MzhjNTAyZjNiOTM4MGNjMGZhOGJmYmQ2ZjFlMWJhNzA. for seqno 2 (Critical Response)
> -- See doc/sip-retransmit.txt.
>
>
>
> [Mar 18 12:35:27] WARNING[3854]: chan_sip.c:1980 retrans_pkt: Hanging up
> call MzhjNTAyZjNiOTM4MGNjMGZhOGJmYmQ2ZjFlMWJhNzA. - no reply to our critical
> packet (see doc/sip-retransmit.txt).
>
>
>
>
>
> I check on the web and see that long time ago, some user experiment had
> same problem.
>
> But I see also that, since version 1.4, this kind of error “no reply to our
> critical packet” wasn’t considered as a Fatal error… So is it normal that
> cause hang up ?
>
>
>
> I’m running Asterisk 1.4.22 and communication was established between an
> Aastra 55i and X-Light
>
>
>
> Thanks for informations.
>
>
>
>
>
> Serge BERNEY
> *Kin SA*
> www.kinonline.net
>
>
>
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