i heard on nmaps long interview you could instead of pinging an ip which is most likley behind a router / firewall and is ignoring the ping request you could send a timestamp / netmask request. Anyone know how to use this?
Also, if anyone knows some tips on getting past firewalls / routers with nmap etc please let me know :) i tried using -f to put the scan in fragments, but did not get much luck with it. thanks