Why does the voice on the asterisk go in one direction?

Question

Asterisk

Hello. There is an Asterisk server and two offices. In the offices themselves, everything works ok. ALL TAs are in the same VLAN If I call from Office N1 (where Aster is located) to Office N2, then the voice does not go (but not to all numbers, everything is ok on some TAs). If from Office N2 to Office N1, everything is ok.
But, we also have Lync (S4B) in our network, which is connected to Aster and calls from it in both directions are also ok.
The question is, what the hell?

Answer 1

The new Grandstream firmware has an option: Codec Negotiation Priority. The default is Callee. Fixed on Caller - it works.

Answer 2

IMHO, the question is for the internet gateway, not for Aster. Mapping and translation of addresses.
The telephony client can be behind two NATs from the PBX server and everything will be fine if the routing is configured correctly.

Answer 3

Well, have you tried searching on your own?
Voip no one way voice, how to set up sip?

Answer 4

The bullshit is that voip traffic must go directly, in the same network. No routing routers between networks and other muddiness. All the necessary integrations into the aster are done by adding additional network adapters to the asterisk.