WatchGuard Firebox/XTM applicances have a finite limit of Proxy Connections available. THe XTM series has a very high limit and should not present a problem. However, we do hear reports of e-Series hardware hitting the limit, and malware outbreaks have been known to trigger the same problem as they 'phone home' or try to spread. To prevent hardware lock-ups and frequently having to reboot appliances, policy should be optimised with a view to limiting the number of connections that get proxied. Frequently, it is a TCP-UDP proxy being used as a 'catch-all' rule that will cause the problem. While it is okay to use the TCP-UDP Proxy in this manner, it is best to deal with unwanted traffic, or traffic that can be allowed through a packet filter rule, prior to reaching the TCP-UDP Proxy Catch-All rule.

If you must use the TCP-UDP Proxy (to allow MSN IM, for example), consider adding packet filter rules to handle:

An example policy using the above advice:

 

If all else fails, there is a scheduled reboot feature in Version 11 onwards. Setup>> Global Settings>> Automatic Reboot.