Linux Troubleshooting Methodology

Studying for the CompTIA Linux+ 005 exam I came across a well known and well used (at least by me) topic; troubleshooting.

Identify – What is the trouble?

Scope – What is the extent of the trouble? One use? One computer? One network? One distro?

Probable Cause – What is most likely causing the trouble?

Test – How can I test my hypothesis about the probable cause?

Plan of Action – If I have proven my hypothesis regarding the trouble; what is the action I need to take to correct the trouble? Given I need to go forward and address the trouble; what impact will that have? Other users? Other computers? The network?

Implement – Execute my plan of action.

Verify – Did my now executed plan of action address the trouble? Does everything that worked before I implemented my action still work?

Preventative – Do I need to look for this trouble elsewhere? Do I need to warn others about this trouble?

Root Cause / After Action – How did I get from the original report of trouble to this point where the trouble has been resolved? If I had it to do over again is there anything I could do in order to resolve the trouble better or faster?