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How firewall rules changed my Google Cloud ping tests

Peter Fast · Published October 10, 2026

Work recorded: October 2026

I tested which traffic could reach two virtual machines, then used a load balancer to distribute requests across three web servers.

Terminal results showing successful pings followed by packet loss after firewall changes

I started by checking connectivity between two virtual machines. The initial internal and external ping tests each received all three replies. Removing the ICMP rule stopped replies to the external address while the internal test still worked. Removing the internal custom rule then stopped the internal replies too.

Distributing requests across three servers

In the second part of the lab, I configured three Apache web servers and a network load balancer. Repeated requests returned responses labeled www1, www2, and www3. I deleted the temporary resources after testing.

Repeated HTTP responses identify the three Apache backends as www1, www2, and www3 — Saved evidence from the completed lab. The temporary cloud resources have been deleted.

The useful lesson was seeing how a configuration change showed up in a test result. The case study includes the screenshots and a more detailed account of the work.