We are attempting to setup 3 sites with a Panasonic TDE100 PBX and Panasonic IP phones.
There are 3 locations, all with static public IPs:
Site A is where the PBX is hosted. PBX is configured with an internal IP (192.168.1.x subnet). PBX is natted to an available IP at Site A for all network traffic (for example, let's say 10.1.1.1) .
Before any Cisco firewalls were implemented, the PBX sat with a public IP configured on it directly (10.1.1.1), and all 3 sites were able to make calls just fine. The issues began when we implemented Cisco firewalls, internal IPs, and started natting stuff.
Site A -> Site B is connected via an IPSec tunnel with Cisco ASA5505's on each end.
Phones at Site B have a 192.168.2.x subnet, and can see the PBX at Site A (via the 192.168.1.x IP over the tunnel) and calls work just fine, both internal extensions and outbound (xxx-xxx-xxxx numbers).
Site C does not have an ASA5505 (international location, ASA not possible at this time). However, the IP phones (same model as Site A and B) have public IP's configured directly on them. Phones at Site C try to connect to PBX at 10.1.1.1 since no VPN tunnel exists.
This setup worked fine before the Cisco's were installed. However, now, Site C phones get dial tone, but once a call is made, there is no audio both ways. Inbound and outbound calls same issue.
Cisco TAC attempted to work on packet capture, and sees all MGCP traffic passing through the ASA to 192.168.1.x PBX IP just fine.