[sr-dev] ICMP port-unreachable for UDP INVITEs

[James Browne]

Thanks, Daniel
That suits me perfectly.
(I didn't see your response until today.)

James

On Thu, 9 Apr 2020 at 17:40, Daniel-Constantin Mierla <miconda at gmail.com> wrote:
>
> Kamailio doesn't do any ICMP processing by itself. I noticed that some
> recent kernels do that when an app tries to send out via UDP to an
> invalid ip/port in the same network and sendto() fails immediately, but
> does detect for other target nodes not in the same local network.
>
> You can lower the retransmission timeout to cope better with such case
> and fail over to next route faster.
>
> Cheers,
> Daniel
>
> On 08.04.20 15:19, James Browne wrote:
> > I've searched, but I cannot find anything recent about this.
> >
> > My kamailio 5.0.8 proxy sends an INVITE downstream over UDP and gets
> > an ICMP port-unreachable response from the UAS.
> > Apparently ignoring this, it re-transmits the INVITEs and eventually
> > times out and sends to the next host (from the SRV lookup).
> >
> > According to RFC 3261 (https://tools.ietf.org/html/rfc3261#section-8.1.3.1),
> >      If a fatal transport error is reported by the transport layer
> >      (generally, due to fatal ICMP errors in UDP or connection failures in
> >      TCP), the condition MUST be treated as a 503 (Service Unavailable)
> >      status code.
> >
> > Does kamailio support handling ICMP responses to INVITEs (and
> > therefore either failing over immediately, or sending 503 upstream
> > immediately)?
> >
> > I don't know for sure the "correct" behavior because the RFC3261 is so
> > old and because ICMP responses are limited in size and therefore can't
> > guarantee to uniquely identify the transactions that caused them.
> >
> > _______________________________________________
> > Kamailio (SER) - Development Mailing List
> > sr-dev at lists.kamailio.org
> > https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-dev
>
> --
> Daniel-Constantin Mierla -- www.asipto.com
> www.twitter.com/miconda -- www.linkedin.com/in/miconda
>