Reverse DNS lookup on a network with a known IP:
http://ws.arin.net/cgi-bin/whois.pl?queryinput=209.177.1.184
RPC scan tool and information, to check on vulnerability to blaster worm:
http://www.foundstone.com/resources/proddesc/rpcscan.htm
SQL Slammer vulnerability scan:
http://www.foundstone.com/resources/proddesc/sqlscan.htm
SuperScan open ports listing.
http://www.foundstone.com/resources/proddesc/superscan4.htm
See what operating systems and webservers each URL is running:
http://uptime.netcraft.com/up/graph?site=gwmail.ramaz.org
On individual computers, to identify what ports are open, and by which applications, run "FPort"
http://www.foundstone.com/resources/proddesc/fport.htm