Strange system freezes - Help!

[Erik Williamson]

Hi All,

I've got a machine with the following description:
Dell Precision 530
Fully patched fedora
Dual P4
Alteon Gigabit nic
Services running:  sshd, vsftpd, apache

Periodically, it goes (mostly) dead.  It looks like this:
I can ping it.
I can nmap it, and the services are all detected
I cannot connect to any of the servers via a client (ie, ssh, ncftp, moz)
I can telnet to the appropriate ports, and get connected. (I forget how to 
make an http server spew to a telnet client, but I've done it before)
Both the terminal (through kvm) and console (serial, through to a 
concentrator on another machine) are dead in the water.
If I unplug the fibre to the nic, the console + terminal report this.  
same for when I replug it in.  Nothing happens with usb devices (just 
trying to see about waking it up)

It's last uptime was a day and a half.  this is the third time it's 
happened.  I'm about to do hardware diagnostics on it, but am 
wondering if anyone has any idea about what else I should look at.

I power-cycled the machine and booted off of a rescue CD - mounting the 
filesystems read-only - but there's nothing interesting that I can see (in 
/var/log, that is).

If anyone knows of something I should look at, probable cause, etc - 
please let me know. 

Thanks for any help - 
Erik.


e r i k   w i l l i a m s o n                     erik at cpsc.ucalgary.ca
 system admin . department of computer science . university of calgary