The primary purpose of a ping request is to identify hosts that are currently active. As such, it is often used as part of reconnaissance activity preceding a larger, more coordinated attack. By removing a remote user's ability to receive a response from a ping request, you are more likely to be passed over by unattended scans or from "script kiddies," who generally will look for an easier target.
Note that this does not actually protect you from an attack, but will make you far less likely to become a target.
Fortifying router security
Step 1: Change the default password!
Step 2: Disable IP directed broadcasts
Step 3: Disable HTTP configuration for the router, if possible
Step 4: Block ICMP ping requests
Step 5: Disable IP source routing
Step 6: Determine your packet filtering needs
Step 7: Establish Ingress and Egress address filtering policies
Step 8: Maintain physical security of the router
Step 9: Take the time to review the security logs
About the author
Chris Cox is a network administrator for the United States Army, based in Fort Irwin, California.
This tip originally appeared on SearchNetworking.com.
This was first published in January 2007