This could be not as good idea since RFC1122 says that every host connected to the Internet must answer to icmp echo requests.
Help me on this: [extract from rfc 1122]: | | | | |S| | | | | | |H| |F | | | | |O|M|o | | |S| |U|U|o | | |H| |L|S|t | |M|O| |D|T|n | |U|U|M| | |o | |S|L|A|N|N|t | |T|D|Y|O|O|t FEATURE |SECTION | | | |T|T|e ICMP Echo Request or Reply: | | | | | | | Echo server and Echo client |3.2.2.6 |x| | | | | Echo client |3.2.2.6 | |x| | | | Discard Echo Request to broadcast address |3.2.2.6 | | |x| | | Discard Echo Request to multicast address |3.2.2.6 | | |x| | | Use specific-dest addr as Echo Reply src |3.2.2.6 |x| | | | | Send same data in Echo Reply |3.2.2.6 |x| | | | | Pass Echo Reply to higher layer |3.2.2.6 |x| | | | | Reflect Record Route, Time Stamp options |3.2.2.6 | |x| | | | Reverse and reflect Source Route option |3.2.2.6 |x| | | | | What is echo server and echo client? Pass Echo Reply to higher layer? Meaning in the IP stack, right? So in short, every host and gateway should implement PING? Even firewalled hosts? So why is there this big discussions about what ICMP a firewall should allow? This document tells you which ones? I am lost... Thanks Raffy