[Serusers] Registrations behind NAT problem.

Andrey Kuprianov andrey.kouprianov at gmail.com
Wed Sep 20 08:27:17 CEST 2006


Thanks a lot Greger!

On 9/20/06, Greger V. Teigre <greger at teigre.com> wrote:
> Three options:
> 1. Turn off ALG if possible (normally is)
> 2. Try to detect that something has been messed up: use
> nat_uac_test("16") to test for source ip:port different from (was it?)
> via (or contact? don't remember). Keep contact as is (so the alg can
> change correctly back), but use fix_nated_contact() on outgoing messages
> 3. Change box
>
> A broken ALG doesn't have to be a problem though, if you can fix it.
> Also you can try stun in your ua, as some ALGs won't touch an already
> correct public message (only works for non-symmetric NATs though).
> g-)
>
> Andrey Kuprianov wrote:
> > I see. Thank you Greger! However, is there anything I can do about it,
> > besides changing the box? :) I assume there should be an option to
> > disable fixing my messages.
> >
> >  Regards,
> >
> >   Andrey.
> >
> > On 9/19/06, Greger V. Teigre <greger at teigre.com> wrote:
> >> Hi Andrey,
> >> As long as you use fix_nated_register(), ser will leave contact from ua
> >> intact, but add received parameter.
> >> Most likely the wireless box has a SIP ALG and the ALG tries to "fix"
> >> SIP exchanges by changing contact and vias.  Many SIP ALGs are broken.
> >> g-)
> >>
> >> Andrey Kuprianov wrote:
> >> > Hi,
> >> >
> >> > Im facing some weird problem, when users register from behind NAT. Let
> >> > me try to break it down.
> >> >
> >> > First of all, Im using ser 0.9.6 and my configuration file is almost
> >> > identical to that of mediaproxy+nat config file from getting started
> >> > bundle. I have asked my friends and colleagues to test my SIP-based
> >> > application behind NAT with their ADSL modems and strange thing
> >> > happens:
> >> >
> >> > 1. While one guy (say user1) has ADSL modem, which gives him address
> >> > of 192.168.0.3, he can register w/o problem. Contact header
> >> > <sip:user1 at 192.168.0.3:5060;transport=udp>;q=1.0
> >> >
> >> > is sent in REGISTER request, and received back with 200 OK as
> >> >
> >> >
> >> <sip:user1 at 192.168.0.3:5060;transport=udp>;q=1.0;expires=3600;received="sip:61.47.x.x:5060"
> >>
> >> >
> >> >   (i have put "x" by myself)
> >> >
> >> > 2. Another guy (user2) has ADSL modem connected to a wireless access
> >> > point. The application sends in Contact:
> >> >
> >> > <sip:surat at 10.0.0.12:5060;transport=udp>;q=1.0
> >> >
> >> > but gets back in 200 OK (attention !!!):
> >> >
> >> >
> >> <sip:surat at 124.120.x.x:41854;transport=udp>;q=1;expires=3600;received="sip:124.120.x.x:43041"
> >>
> >> >
> >> >
> >> > It gets Contact with a public IP back, which is not the case with
> >> > user1. How come?
> >> > I *wonder* why this is happening... Some kind of weird NAT?
> >> >
> >> > I'd really appreciate if anyone can shed some light on this issue.
> >> >
> >> >   Bests,
> >> >
> >> >     Andrey.
> >> > _______________________________________________
> >> > Serusers mailing list
> >> > Serusers at lists.iptel.org
> >> > http://lists.iptel.org/mailman/listinfo/serusers
> >> >
> >> >
> >>
> > _______________________________________________
> > Serusers mailing list
> > Serusers at lists.iptel.org
> > http://lists.iptel.org/mailman/listinfo/serusers
> >
> >
>



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