How Ping Works (ICMP)
Network Fundamentals
Overview
Ping sends ICMP Echo Requests and observes Echo Replies or errors. A successful test demonstrates a specific path at that moment, not that every application works. Policy can block ICMP while allowing HTTPS. A complete exchange needs a usable return path as well as an outbound route.
Protocol stages
- 1Resolve next hop
- 2Echo Request
- 3Forward path
- 4Echo Reply
- 5Return path
Interactive exercise
Knowledge check
A server allows HTTPS but blocks ICMP. Ping times out. Which conclusion is justified?
Related practice
Lab: connect-two-pcsEducational model — not real hardware, traffic or official certification.