View Full Version : Simmetric NAT

10-04-2006, 09:53 AM
I have a Quadro4x behing a ADSL. The Quadro detects simmetric NAT configuration. When I try to do call to Epygi's SIP server I got no voice in return. Is thereany way to work arround this issue?


10-04-2006, 04:44 PM
There are few of NAT status that can't work with SIP:
- Symmetric NAT
- Symmetric Firewall
- Blocked UDP

If you experience Symmetric NAT, you can try to configure the ADSL
router to forward port 5060 to your quadro

anyway what kind of ADSL router do you used ?

10-06-2006, 06:39 AM
It is a BEFSR11 Linksys under the customer's ISP administration, so I don't have access to it. I requested to the ISP to forward UDP 5060 to 5099, but still have the same effect.After the Quadro discovers the connection topology, it always register usinga 5 digits udp port (i.e. ).

I have configured a FWD account using the ITSP configuration wizard and I can make calls to registered numbers within this domain, but I don't know howto pass calls to Epygi's SIP server through FWD.


10-20-2006, 02:09 AM
Comstor is completely right - SIP cannot work work through symmetrical NAT if there is no static mappings on NAT router.

But I have to add two things to what comstor has told here:

1. Forwarding only SIP port is not enough. You should forwartd also all RTP ports within the RTP range.

2. After configuring the port forwarding on NAT router, you may have to correctly configure the NAT Traversal on Quadro using the manual NAT traversal, not STUN.