strange reboot on woody

[Haim Ashkenazi <haim@babysnakes.org>]

Hi

I've got a server at our ISP's server farm which rebooted last night. I've
contact my ISP and no one there did nothing, also it wasn't a power failure
because the reboot is written in '/var/log/syslog':

...
ov 26 22:26:16 ns-ilweb1 init: Switching to runlevel: 6
Nov 26 22:26:19 ns-ilweb1 qmail: 1069878379.427182 status: exiting
Nov 26 22:26:20 ns-ilweb1 ntpd[32551]: ntpd exiting on signal 15
Nov 26 22:26:22 ns-ilweb1 exiting on signal 15
Nov 26 22:28:09 ns-ilweb1 syslogd 1.4.1#10: restart.
...

I've run chkrootkit (last version from unstable) and it didn't find
anything. I've gone to the logs and didn't see nothing suspicious.
(messages, wtmp, faillog, authlog, kern.log).

also, nothing suspicious in '/root/bash_history'.

Is there anything else I can do to check why it rebooted suddenly?