[OpenSIPS-Users] Source port in SIP replies

[Саша Александров]

Hi, Bogdan!

I sent pcap to your address directly, in order not to disclose real ip
addresses and to throw files to the list.
I tried to study the code, and yes, it appears that it can not change the
port freely...
The strnage thing is, that this problem appeared suddenly, and then suddenly
disappeared - without my interaction.
Unfortunately, only the capture that I sent exists. I noticed that the src
port is different only when the problem already went away.
Looks like some kernel/system flaw...
iptables do not change packets - there is only an ACCEPT input chain for the
operator's address...
Weird...

--
Regards,
Alex

2010/10/6 Bogdan-Andrei Iancu <bogdan at voice-system.ro>

> Hi Alexandr,
>
> Alexandr A. Alexandrov wrote:
> > Hi Bogdan,
> >
> > Well, this confuses me even more...
> > I though that in case opensips can not open socket on the port it
> > listens on, it tries to open a socket on a port where it can, and then
> > send the packet out...
> >
> all the local ports are open at startup time - there is no local socket
> created at runtime (for UDP).
>
> I'm really sure that opensips is not messing with the ports, this is why
> I was asking for the pcap....just to check what happens at network level.
>
> Regards,
> Bogdan
> > This would not break any standarts, AFAIK (even though firewalls might
> > get crazy about this, which is, pitifully, my case).
> >
> > Regards,
> > Alex
> >
> >
> > 06.10.2010 15:26, Bogdan-Andrei Iancu:
> >
> >> Hi Alexandr,
> >>
> >> Alexandr A. Alexandrov wrote:
> >>
> >>
> >>> Hi!
> >>>
> >>> I ran into a pretty weird situation last day. I'm using opensips-1.6.2
> >>> as a load balancer for several * servers.
> >>> Everything worked fine for months, but suddenly opensips started to use
> >>> ports like 56827 or 51234 (does not matter, just non-default, not the
> >>> one it is listening on). And the operator's system does not allow such
> >>> replies, it just drops them.
> >>> Opensips is listening on port 5070 on my system.
> >>>
> >>> Invite comes like:
> >>> User Datagram Protocol, Src Port: sip (5060), Dst Port: vtsas (5070)
> >>> INVITE sip:xxxxx at my.ip:5070;user=phone SIP/2.0
> >>>
> >>> Reply goes like:
> >>> User Datagram Protocol, Src Port: 52795 (52795), Dst Port: sip (5060)
> >>> SIP/2.0 100 Giving a try
> >>>
> >>> Normally src port is always 5070.
> >>>
> >>> So, the questions are:
> >>> - under what conditions does opensips decide to invent a new port?
> >>>
> >>>
> >> under no conditions - it will use only the defined interfaces from
> cfg...
> >>
> >> Are you sure about that port changing ? could you provide a pcap showing
> >> this ?
> >>
> >> Regards,
> >> Bogdan
> >>
> >>
> >>
> >>
> >
> >
> > _______________________________________________
> > Users mailing list
> > Users at lists.opensips.org
> > http://lists.opensips.org/cgi-bin/mailman/listinfo/users
> >
> >
>
>
> --
> Bogdan-Andrei Iancu
> OpenSIPS Bootcamp
> 15 - 19 November 2010, Edison, New Jersey, USA
> www.voice-system.ro
>
>
> _______________________________________________
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> Users at lists.opensips.org
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>



-- 
С уважением, ААА.
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