Restricted cone

I have been working on getting 2 GS BudgeTone 100 to work both behind NATs. Am I suposed to be able to do it using only a STUN server?

Right now i need to use the STUN server and also open ports on the NATs for the audio to go through. When the ports are closed and I use the STUN, the phone status says Restricted Cone and the audio is blocked. If i open the RTP port the status says full cone and it works. But shouldn t it be working only by using the STUN server and leaving the ports closed?

Thank you

Can you access any logs on the firewall and see why it is blocking it? It sounds like STUN is doing a good job of detecting NAT but the packets are getting blocked anyway.

I think that one of the NAT was Symmetric
I have to test some more but am i suposed to be able to connect one phone to the oher using only STUN?

BTW i am using Asterisk for making the call