We recently received a Fortinet FortiGate 60C unit as an RMA replacement for a 60B. About 10 days after we received it the unit began to stop passing Internet traffic at seemingly random intervals. The only solution we found was to restart it.
Fortinet support suggested that the reason the unit was freezing was because it was going into conserve mode which happens when memory usage gets to 80%. We reduced the number of policies in use and changed UTM inspection mode from proxy to flow based. I also shut off dns-upd session helper. The resources now level out at about 20% CPU and 70% memory.
And still the device randomly freezes and stops passing traffic. We are running 4.0 MR3 Patch 5, NAT mode, standalone, one internal and one external interface, no virtual domains. UTM: Antivirus, Web Filter, Application Control, IPS, Email Filter. Also, we are using per-IP traffic shaping. We are logging to disk and not to memory. This is on a network of 113 clients, 63 of whom are regular Internet users.
The only consistent "fix" I have found is to reload the firmware. This buys about 10 days of uninterrupted Internet access.
If anyone has suggestions of what to try to get this thing to stay up I would very much appreciate it. My biweekly Fortinet support ticket ritual is becoming tiresome.