Timeout vs Unreachable Explainer

Timeout or unreachable — the two mean opposite things about where the fault is.

What you paste

Parsed in your browser — never uploaded

Result

No error message recognised

Nothing in that output matches one of the errors ping reports. The reference above covers all of them. The distinction worth carrying away is between a timeout and an unreachable: a timeout is silence, and an unreachable is a router actively telling you it could not deliver — which means the path is working well enough to carry that message back, and makes it the more diagnosable of the two despite sounding worse.

Diagnostic telemetry
Request timed outThe reply was lost, the destination is ignoring ICMP, or a firewall is dropping the probe silently. Silently is the key word — a device that drops without replying leaves exactly this.
Nothing came back within the wait, and nothing on the path reported a problem.
Destination host unreachableUsually the last router before the destination, which knows the subnet and got no ARP reply — so the host is off, disconnected, or does not exist at that address.
A router on the path sent back a message saying it could not deliver the packet.
TTL expired in transitA routing loop, or a path genuinely longer than the TTL allows. A loop is much the likelier of the two.
The packet was passed between routers until its hop limit ran out.
Unknown host / could not find hostA DNS problem rather than a network one. The packet never left.
The name could not be resolved to an address, so nothing was ever sent.
Network is unreachableNo default gateway, or an interface that is down. The packet did not leave your computer.
Your own machine has no route toward the destination.

What this cannot tell you

  • Explains the message. It cannot tell you why the device behaved that way, only what the message establishes about where to look.
  • A host that will not answer a ping frequently serves traffic perfectly. ICMP is blocked by policy far more often than by fault, so a timeout is weak evidence of a problem.
  • Parsed in your browser. Nothing is uploaded, and the output you paste is not stored.

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