Last night, my RH 9.0 server suddenly rebooted. In the /var/log/messages, I only found this :

May 5 02:55:03 earth shutdown: shutting down for system reboot
May 5 02:55:03 earth init: Switching to runlevel: 6
May 5 02:55:04 earth shutdown: shutting down for system reboot
May 5 02:55:04 earth atd: atd shutdown succeeded

and the rest is normal boot message

This machine does not have any local user ... only me.
Does not have a lot of running services :
- apache 2.0.49
- thttpd
- openssh
- snmpd
- pure-ftpd

Cant find anything in the log :( Anyone how this happen ?

[root@earth log]# last | more
pot pts/0 c3eea3d45.cable. Wed May 5 08:44 still logged in
reboot system boot 2.4.26-HN-1.6-P4 Wed May 5 02:55 (06:19)
pot pts/1 c3eea3d45.cable. Wed May 5 01:13 - 01:42 (00:28)

maybe a datacenter tech rebooted it for an upgrade :? Or maybe you have a worm of some sort, run chkrootkit and rkhunter

Sudden reboot can be a bad power supply, or a very short/fast drop in the power line (if no UPS), or heat problems. As far as software goes, the kernel will spontaneously reboot any time there is a triple exception, which can happen when ram is bad (try memtext86, http://www.memtest86.com/) or the cpu or chipset overheats.

happened to me years ago when i couldnt afford good hardware... seems to almost always be improper cooling or power. Many chips & motherboards shut the system down to prevent damage when they redline. My asus did this when i had a bad power supply. get a probe (asus has 1 that kicks *** for free).