you also have to understand a few things about "pinging" It all depends on what the server is set up for, if its your webserver you would leave it for the most part, is it DMZ database server -> then probably mot, is it something on your internal network, then nO. even if its a webserver blocking ICMP echos will be of little consequence when port 80 is replying to Syns. There are more or less a few methods to determine if a host is alive, ICMP pings and TCP/UDP packets from my limited understanding.