Our network has a firewall protecting a WAN link. The firewall runs in Transparent mode. A new firewall was added to act as a DMZ to the existing firewall. This firewall is running in routed mode. All connectivity is good but we have a problem with a server that will not backup. The connection it established through the first firewall and into the DMZ and all seems ok. After 2 hours the back up fails. There are no error messages and I have allowed any ip traffic in both directions.
Any ideas why this is happening?