I have a PIX506E as the firewall between my LAN and my ISP. The power supply failed and while waiting for a replacement, I replaced the PIX with a Netgear router. This worked for what I needed (Internet access for browsing and email). When I went back to the PIX all desktops and servers are able to access the Internet as before except one server, my Exchange Server. No email in or out. Browser says page not found. I can ping the Pix and login to the PIX configuration. I cannot ping DNS server (outside). The gateway address, LAN mask, and DNS addresses are correct on the server. The MAC address is correct for the PIX IP address in the ARP table. The PIX configuration seems to be the same as it was before (although not 100% certain). I have rebooted the server. Ths is a Windows NT 4.0 server. I can return to the Netgear router and it works.
Can anyone think of something else to try to resolve this problem?