So we had a site to site vpn between two old sonicwall 2040 firewalls. The domain runs over the vpn. So it's all the same domain. The ip phones on one end connected to the phone system on the other just fine. They aren't going over the internet. Very average setup. Nothing difficult.
We replaced one of the firewalls with a new Sonicwall NSA 2400. Everything is connecting over the vpn except the ip phones. I have gone as far as to open all services, all to all, between the two sites and put that policy at the very top of the list. Still nothing.
If I plug the old firwall back in, everything works.
The new firewall does have some special voip settings, but Sonicwall said those are only for special cases. They should be left alone and ip phones over vpn should work fine as is. Our phone vendor also took a look and says everything on the phone system works fine, and our phone setup is very basic. He looked at the voip specific settings on the firewall and also confirmed we didn't need to touch those.
So what could I be missing? If all services are open, any source to any destination, and everything else works over the vpn...what could it be?
Any help appreciated!