[SR-Users] tcp hangup

Andrei Pelinescu-Onciul andrei at iptel.org
Tue Apr 5 15:16:02 CEST 2011


On Apr 05, 2011 at 16:10, Juha Heinanen <jh at tutpro.com> wrote:
> i turned out that the problem below was caused by a firewall that
> blocked tcp session if it had been idle for a few minutes.  the problem
> went away when i reduced tcp_connection_lifetime from 3610 to 120 sec.
> 
> i don't know if it possible to configure tcp_connection_lifetime on per
> connection basis.  for example, tcp connection to UA could have
> tcp_connection_lifetime=3610, since tcp session is kept active by UA
> sending crlfs, whereas tcp connection to another proxy could have a
> shorter tcp_connection_lifetime.

No, it's not possible to set it on a per connection basis.
It could be done (at the price of an extra int per tcp connection), but
the bigger problem is how to distinguish between proxy and UA
connections.

Andrei
> 
> -- juha
> 
> -------------------------------------------------------------
> 
> > > i did some more debugging and wireshark shows that the 3.0 sr does not
> > > even try to send anything to the 3.1 sr over the tcp connection although
> > > netstat now tells at both hosts that the connection is established.
> > > instead sr 3.0 replies immediately after receiving invite from ua:
> > > 
> > > SIP/2.0 477 Unfortunately error on sending to next hop occurred (477/TM)
> > > 
> > > there is no related messages in syslog.  perhaps tcp stack on 3.0 host
> > > has not got acks for earlier packets and just waits there.
> > 
> > The most likely candidates are:
> > - blacklisted destination (due to some previous error).
> >   You could check it with sercmd dst_blacklist.view or
> >    dst_blacklist.debug.
> > - some local firewall rules on the OUTPUT chain
> >   running out of memory (but it's strange that you don't get any log
> >   messages)



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