FreeBSD 5.0 Box rebooting itself

[dnet19650]

I have a FreeBSD 5.0 live system that has rebooted itself twice (the last two weekends). I had the system running for sometime with this just starting two weeks ago. I do make adjustments to the spam filtering constantly. The system logs show nothing to a reason why. It does not even have any comments about the system going down just comments about the system comming back online. Then it reports the system was not shutdown properly. I would first think it was a power failure but it is online with other server on a large battery backup system. Here is my setup
FreeBSD 5.0 Release
-DNS Bind 8.0
-DHCP
-Qmail /-SpamAssassin /-ClamAV /qmail-scanner-queue
Main service is email with spam and virus scanning for ~ 80 accounts.
Anybody got some suggestion on where I could start looking.
My first plan is to download the lastest updates. But it is a live system and I would hate for it to go down for any large amount of time.

 

[zum]

Are you sure the box isn't getting to hot? I was having similar problems until I realized the box was over heating so I moved it.

Zum.

 

[dnet19650]

Don't believe so. I have all the server in a temp controled
room. I am woundering if this might be from the Bind 8.0 security bug. I need to patch it. Is this the kind of thing that would happen on a denial of services attack? Just seems strange, you would think it would just crash. Rather then reboot.