Two sip phone ring, but can not hear each other!

Hello, Guys:
I set a softswitch using asterisk. I have tested the sip phone internallly. the sip phones can make calls each other within LAN. when I use the same number from outside as a homeuser to regiester in our server, the two phones ring, but can not hear the voice. I think it’s Nat problem. my asterisk has a public IP. But I have no idea how to make asterisk work as a softswitch. anyone knows how to solve this problem, please give me a help! thanks!

I’ve got the same problem from the sounds of it… still haven’t nailed the issue…

Usiung X-lite soft phones…

Everything works fine on the LAN… but try doing it beyond that zone and I can only recieve but not transmit.

And thats from Softphone (SIP) to a physical phone number (POTS?).

I would assume that SIP to SIP connections would yield a dead silence effect.

Helllo, friend:
I tested under one is private ip and one is public IP. I solved this problem by adding anohter network cards and set a ip for public without router. so a asterisk server has two ip. one is private ip and another one is public ip, which can connect to the asterisk with public IP.
you try it!