ICMP communications are used for network troubleshooting purposes. By default, all ICMP communications are allowed. For the detailed description of ICMP messages, please refer to:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/xpehelp/html/xeconconfiguringicmpsettingsinwindowsfirewall.asp
If you need to block or to allow ICMP communications, follow these steps:
The predefined rules for ICMP communications are listed. The S (status) column shows the icon if the firewall blocks the packets that match the rule, and the
icon if the firewall allows the packets that match the rule to pass through.