I have a server running Ubuntu 10.04 that is rebooting several times a day it seems, and I can't figure out why. It doesn't appear to be a graceful reboot either, because some of the services complain about a crash when I look at their logs. I am looking through /var/log/messages and I see a lot of strange kernel statements as follows:
Jul 27 13:28:41 it-admin kernel: [ 5198.213173] r8169: eth0: link up
Jul 27 13:20:38 it-admin kernel: [ 4716.055043] r8169: eth0: link up
Jul 27 13:29:37 it-admin kernel: [ 5253.309017] r8169: eth0: link up
Jul 27 13:30:29 it-admin kernel: [ 5305.593953] r8169: eth0: link up
These are printing out every few seconds as you can see. I've never seen the kernel say this before, so I am wondering if it has something to do with it.