Free Online Network, Security, and Webmaster Tools.

[cba]

Somehow I stumbled across this site on digg searching for 'dns lookup tools', it only had a few diggs: Network, Security, and Webmaster Tools

I know other sites like this, but they all seem to charge for their tools. Does anyone know of any good sites that share their tools for free (like the one I linked to above)?

I'm sorry if this is the wrong forum to ask, but I wasn't sure where I should ask, and I thought I'd receive more attention if I shared a site I already know of.