I have two offices with a PIX 515 at one end and a PIX 506E at the other. On the site with the 506E we also have call manager express running with 6+ IP phones connected. On the site with the 515 there is one Cisco 7940 IP phone which connects to the Call manager via a VPN tunnel between the 515 and 506E and this is all working fine.
I'm currently trying to change the 506E for a Cisco ASA 5510. I have everything working fine. VPN comes up ok and traffic flows between PCs and servers without any problems or disconnects. The problem is the IP phone, It can't maintain a stable connection to the Call manager. It will sit happly for 10 mins you can make calls ok and then it will lose connection to the CM and eventually reboot. Other times it will be ok for 40 mins before it starts playing up.
If I revert back to the PIX 506E everything work fine again, it just happens when the ASA is involved.
Any ideas or settings I could make to resolve this?