A support technician uses the ping utility on a system that is online, yet no response is received. What should be allowed through a firewall, for ping to operate correctly?

The Internet Control Message Protocol (ICMP) should be allowed through a firewall, for ping to operate correctly.

In conclusion, the Internet Control Message Protocol (ICMP) should be allowed through a firewall, for ping to operate correctly.

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Internet Control Message Protocol (ICMP) Echo Requests

Explanation:

A system that has Windows Firewall or antivirus or other third party antivirus enabled with their configuration setting set to default, ping command from another device will not be able to see if the device with an enabled firewall is alive.

The ping command sends Internet Control Message Protocol (ICMP) Echo Request to a destination device after the destination device will reply with a Reply packet. However, by default, firewalls, such as Windows firewall blocks ICMP Echo Requests from the external network and pinging will  work when the firewall is disabled or an exception is created that lets ICMP Echo Requests pass through the firewall.