Problems using the preferred client (no voice)

[jakob6]

Hello,

we have a problem using the one x preferred client in our avaya / one x portal enviroment. The client can succesfully connect to the one x portal server using the voip function. we also can start a call, but here is the point we are stuck. On both sides we have no voice signaling, nobody can hear each other. in the preferred client under "details" the "remote" ip adress of the Avaya IPO is the local ip adress from the company network and i think i should be the public ip adress of Avaya IPO. We already checked the network topology and used the stun function to set the firewall type and the public ip adress. but we still get the internal ip adress in the preferred application. When i connect to our company one x portal i get external the correct public ip adress and not the internal. The RTP Ports are forwarded and open, the client is using a correct port (checked this in the details section in the app)

Did anyone has an idea where the problem could be?

Thanks

Informations:

We are using the Avaya Application Server in the newest version
We are using a IPO 500v2 10

[jakob6]

Additional information:

The IPO and the one x portal server and not in the same location, but the networks are connected by a side to side vpn.

We are using a split dns and the FQDNs are configured correctly.
Internal they show the internal addresses of the ipo and the one x server and external they show the public ip adresses of the locations