Diagnosis and fixes

Troubleshoot

Each problem follows the same structure: what's happening, why it might be happening, how to check and how to fix it. No fluff.

🐧 Linux

Linux

Permissions, owner or execute bit.

Linux

Package not installed or PATH incomplete.

Linux

Service down, wrong port or firewall.

Port busy, invalid config or permissions.

Access denied to an existing resource.

Nonexistent route or misconfiguration.

Generic failure: check the logs.

The device does not receive an IP automatically.

There is connectivity but domains don't load.

Access/trunk ports and 802.1Q tagging.

Diagnose by layers: physical, IP, gateway and DNS.