[OpenSER-Users] nat_uac_test("31") not enough to detect with some consumer voip passthrough routers

[Raúl Alexis Betancor Santana]

El Thursday 27 March 2008 17:13:38 Mike Fedyk escribió:
> Hi,
>
> Some of our customers have been connecting behind NAT routers that mangle
> the sip headers but don't keep the ports open.  I've added checks on the
> source port to catch this case.  Has anyone done something similar or
> better?  It'd be nice if this could be added as a flag to nat_uac_test() if
> it is a common test and there isn't already a better way.
>
> Here is the code I've used to handle my registers.  I need to do more
> testing once I can get some of these routers in my lab to see how this
> affects call processing, not just registering.

Dear Mike,
I could save you tons of hours trying to solve that problem, ANY router on the 
market that do SIP ALG (sip mangling) do it well, ALL of them (cisco, zyxel, 
netgear, etc.) do it the wrong way or worst than wrong .. :-(

My advice to you, if you have customers that have that broken routers, 2 
solutions:

- Disable SIP ALG support (most of them could disable that feature)
- If SIP ALG could not be disable, tell your customer to change the router.

Another solution is what it is done by Betamax and it's clones ... just IGNORE 
all the information on the SDP about IP media sources, tell you customer's UA 
to send all the traffic to your RTP proxies and then wait for that RTP before 
knowing to were you have to send yours. Also this "solution" have its own 
tons of problems, the bigger of them is that it totaly broke SIP standar.


-- 
Saludos.

Raúl Alexis Betancor Santana
Dimensión Virtual S.L.