[OpenSER-Users] RE: NAT question

[Papadopoulos Georgios]

Hi Inaki,

Why would you leave out the "4" flag test in nat_uac_test() for the replies? 
Of course if I leave out the "2" test then my example works (I have tested it) but I am afraid that this will break some other NATed senario. And if leave out the "2" test, should I also leave out the "16" test?

Best regards

George

> ------------------------------
> 
> Message: 4
> Date: Wed, 8 Aug 2007 11:53:46 +0200
> From: I?aki Baz Castillo <ibc at in.ilimit.es>
> Subject: Re: [OpenSER-Users] NAT question
> To: users at openser.org
> Message-ID: <200708081153.46621.ibc at in.ilimit.es>
> Content-Type: text/plain;	charset="iso-8859-1"
> 
> El Wednesday 08 August 2007 10:30:54 Papadopoulos Georgios escribiσ:
> > Hi Bogdan,
> >
> > I understand that 200 OK should not be fixed by proxyA. Maybe what I
> > don't understand is what nat_uac_test("2") does and when to use it.
> >
> > Following is an example where
> > clientA = demo1 at altecnet.gr
> > clientB = sip_test_1 at i-call.gr
> > proxyA = 213.5.43.4
> > proxyB = 213.5.43.134
> >
> > When proxyA goes in the onreply_route for the 200 OK, 
> nat_uac_test("23")
> > returns true (I guess because of the "2" flag) and proxyA fixes the
> > contact again which is wrong. So, would it be safe to use
> > nat_uac_test("23") for the requests and nat_uac_test("21") for the
> > replies? I am afraid this would break the simple case with 2 NATed
> > clients and only one proxy:
> > clientA ------> proxyA ------> clientC
> 
> 
> Good point. As I think, the correct NAT test for replies is:
>   nat_uac_test("1")
> so we just check if <Contact:> header does contain an RFC1918 
> IP address 
> (private IP address).
> 
> In your case it will work since the <Contact> modified by 
> proxyB will contain 
> a non private IP so the NAT check (nat_uac_test("1")) in 
> proxyA wont detect 
> the repliy as behind NAT.
> 
> Maybe others test could be done, but I think they should no 
> valid test that 
> just compare the received IP with the IP of the contact since 
> both could be 
> public IP but different, in which case shouldn't be 
> applied "fix_nat_contact".
> 
> 
> Regards.
> 
> 
> 
> -- 
> Iρaki Baz Castillo
> ibc at in.ilimit.es
> 

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