[OpenSIPS-Users] Comparing client_nat_test with nat_uac_test

Bogdan-Andrei Iancu bogdan at voice-system.ro
Mon Jun 1 12:53:29 CEST 2009


Hi Thomas,

Thomas Gelf wrote:
> Another thing I stumbled over is one missing test in client_nat_test():
> test 1 is the same in both modules, nat_traversal's test 2 corresponds
> to 18 (2 & 16) in nathelper's nat_uac_test,
I found useful such a separation because in some cases (asymmetric GWs), 
a GW may be detected as nated just because it advertise a different port 
in VIA. So, I would like to have the control over these tests.
>  test 8 (search RFC1918
> addresses in the SDP payload) has no equivalent in client_nat_test().
>   
again, I do use this use this test, but not for detecting the private 
IPs, but public once - this is useful when doing chains of RTPproxys + 
mediaproxy + whatever other media relay.

example is : UAC1 (nat) ---- proxy1 (forces RTPP as caller is natted) 
----proxy2 (forces RTPP as callee is natted) ---- UAC2(nat)

here, to avoid deadlock between the 2 media relays, you detect if a 
public IP is in the SDP and start using that IP right away instead of 
waiting to receive traffic (in order to discover the RTP peer).

Regards,
Bogdan
> Is test 8 useless? Is anyone aware of scenarios where RFC1918 could
> appear in SDP, even with a correct SIP header? I know that EVERYTHING
> is possible with a braindead ALG - but are there other situations where
> this could happen? I wasn't able to figure out such an example, so
> client_nat_test("7") should probably suffice for all cases.
>
> Is this assumption correct?
>
> Best regards,
> Thomas Gelf
>
>
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