[Serusers] UAs and SER behind NAT

[Michal Matyska]

Copy&paste from nathelper's README: 

1.5.6. nat_uac_test(mode)

   Tries to guess if client's request originated behind a nat.
   The parameter determines what heuristics is used. If flag 1 is
   set, the "received" test is used -- address in Via is compared
   against source IP address of signaling. If flag 2 is set,
   Contact header field is searched for occurrence of RFC1918
   addresses. Both flags can be bitwise combined, the test
   returns true if any of the tests identified a NAT.


So in short, if you call nat_uac_test("1"), you will get true if it has really
passed the NAT...

Michal

On Sat, Dec 03, 2005 at 11:50:24PM +0100, Ladislav Andel wrote:
> Hello,
> I'm sorry for this basic question, but I have SER running on my LAN with 
> (RFC1918) addresses with UAs on the same network.
> Then there are UAs registering from behind NAT to this SER on the LAN 
> network.
> (SER is not listening on any public IP and it's just used in the private 
> network)
> I came across this issue. If a UA on the LAN network is registering to 
> SER the logic of ser.cfg recognize the UA is behind NAT
> after nat_uac_test.
> If I want to introduce NAT traversal with RTPproxy for this private 
> network nat_uac_test will always return that the UA
> is behind NAT because it has RFC1918 IP address. The RTPproxy will be 
> used at all times for UAs on the network or even I introduce STUN for 
> NATed UAs
> 
> I know this is not a common usage of SER because it is invented to be 
> used on the global internet but I was just wondering is there any 
> possibility
> not to use RTPproxy at all times for UAs on the private network?
> Maybe this is a silly question but it would help me for my testing 
> purposes with SER where I will not have to use my setup with usage of 
> public IPs.
> 
> Thank you for any thoughts.
> Ladislav
> 
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