[asterisk-users] Cisco 7960 become UNREACHABLE behind pix firewall

[James Lamanna]

Hi,
I have about 10 Cisco 7960s behind a PIX 506E (IOS v6.3) firewall.
After some period of time, asterisk says that some of them are
unreachable, and the phones lose their registration.
The only way to make the phones recover is to clear the NAT
translation tables for the phones on the PIX (clear xlate...)
Does anyone know how to fix this? As you can imagine, it is quite
annoying. And it does not happen to all the phones either.

sip fixup is enabled on the PIX

phone config parts:

nat_enable : 1
nat_received_processing : 0
nat_address: [public ip of PIX]

Thank you.

-- James
(Please CC me on all replies)