my linux centos m/c is hanging
 

I have got a Centos linux m/c on which I am running proxy.
Though everything is working fine but all of a sudden the m/c hangs completely and I am neither able to connect to it remotely nor locally.
I have to hard boot it.

As i am new to linux os. Kindly help me how to trouble shoot it i.e. which logs to be checked whether it is a h/w problem or a s/w problem.

Thanks

You should look into /var/log/messages file to start with. You will have basic idea what the system is going through.

I am attaching a log file kindly tell if there is some problem with my m/c. One more thing the CMOS battery was weak and the system time was always showing incorrect insipte on my correcting the time. Could this be the reason for my m/c hanging up.

Well, as of 16:10:59, the eth0 NIC started going up and down continuously, so what was the system doing around that time.