I called RS support yesterday and actually got someone who knew what they were doing. anyway he told me about this link which I thought was pretty helpful so thought I would pass it on..

www.dnsstuff.com

Here's my favorite:

http://www.samspade.org

Here is mine: :D

http://network-tools.com/

I've been working on my own set of tools. Nice links to get more ideas. :D

EDIT - Never mind, I found it.