I am running a PIX 515 with OS 6.3(4).
The PIX has three interfaces outside, inside and dmz.
There is an exchange mail server in the dmz area. Its IP add is 192.168.1.10. And it is natted to an outside address like 188.8.131.52 for example. At the beginning, everything is working fine. But after some time, the mail server will not be able to access the internet. I use my computer to connect to the internet directly using the 184.108.40.206, the link is fine and I can access the internet. After changing the outside nat address to 220.127.116.11, the mail server is working again.
Can anyone give me a clue? I'm really frustrated about this problem.