Server overloaded with "Unknown console command"

For the past week my white-listed server has been stopping ungracefully. After some investigation I'll find thousands of "Unknown console command" lines logged in a few second period (6500 lines+), just prior to the crash:

This happened a few months ago and I was never able to track down the source of the problem. DoS attack? One of my players using client-side mods? I'm at a loss.

CB#928 on Ubuntu, commercial server host. More info available upon request.

 

The problem continues. Any ideas before I let this post slide into oblivion?

 

Maybe this? Not too sure.
http://forums.bukkit.org/threads/me...-7-returns-unknown-command-messages-818.1753/

 

Thanks for the suggestion. I'm going to try the author's "Commands Logging" plugin initially to see if any commands are run prior to the issue. Come to think of it, I like the idea of having commands logged regardless.

 

Maybe:
1.plugin is lagging
2.that command is not available to you
3.that file in specifc plugin is wrongly confugured

I had it once try these !

 

What's with the necropost??