Identify IP address

From: Clark (clzahn@mindspring.com)
Date: 03/04/02 

From: Clark <clzahn@mindspring.com>
Date: Mon, 04 Mar 2002 00:06:23 -0800

I've forgotten the command to identify an IP address. Could someone
enlighten me? According to my website access log I'm getting Nimba worm
type requests from a certain IP address.

Thanks,

Clark Zahn