On windows server 2008, Vista and Windows 7. Ping requests are blocked by the firewall by default. To enable ping requests (icmp), you can either run the following command “netsh firewall set icmpsetting 8″ as an administrator or open control panel -> administrative tools -> windows firewall with advanced security. Once loaded, select inbound rules from the left hand pane. From this, select “File and Printer Sharing (Echo Requests – ICMPv4-In)” and click “enable” from the right hand actions pane. Note that you may have multiple of these rules here, e.g. for the domain and private profiles. Select the relevant one, depending on where your requests will come from.
Note, as security recommended practices, you should only enable ping requests when required, and shouldn’t leave open.