[OpenSER-Users] nathelper without rtpproxy

[Iñaki Baz Castillo]

El Tuesday 31 July 2007 11:59:42 Nhadie Ramos escribió:

> Hi Inaki,
>
> How about those Linksys DSL router? Does STUN work on them?

I don't know Linksys DSL routers. I jsut can tell you that other SIP NAT 
oslution is using routers with ALG, that is, the router modify the SIP 
headers (Contact header, RTP media contact...) but in MANY cases they wrong 
terribly bad. For example, my home router (Zyxel P660) has ALG enabled by 
default and it works BAD BAD BAD, it writes things as:
   Via: SIP/2.0/UDP xx.xx.xx.xx:2867760;branch=z9hG4bK54e0ac3f;rport
Look at the port 2867760 !!!!!!!!!!!!! XD

So the solution in this router (thanks to JesusR) is dissabling ALG via 
telnet:
  ip nat service sip active 0


> What other
> tool can I use besides STUN?

Note that the target of STUN is to appear as if the device has public IP. So 
if a device is using STUN the OpenSer will not know that it's behind NAT 
(this is great in fact). So dont worry so much about STUN. The only problem 
is cases where the router has symetric NAT that is not valid for using with 
STUN. In this case you need ALG (but they are mos terrible) or server side 
NAT helping (rtp proxy and so).


> Also, does anyone have a sample STUN config on a PAP2 maybe i'm doing it
> wrong.
> Do I have to enable NAT Mapping? Do I handle VIA Hdrs? etc. etc. Those
> are parameters i see on enabling the STUN.

The only thing you must configure is:
 STUN Enable: yes
 STUN server: any STUN server (as stun.ekiga.net)

No more is needed to change (depending in your OpenSer configuratio, of 
course, but for example I need no changes).

-- 
Iñaki Baz Castillo
ibc at in.ilimit.es