Run the outward sequence on a healthy machine and record what each step proved

short · 40 min · Objective 5.1

Task

Execute the layer-by-layer sequence on a working connection first, so that each command's healthy output is known -- because you cannot recognise an abnormal result without having seen a normal one.

Steps

  1. Run each step of the sequence in order and capture the output into lab/seq/step-1.txt through lab/seq/step-8.txt.
  2. Record in lab/seq/proved.csv with header step,command,what_it_proved,what_it_did_not one row per step.
  3. Record the healthy signatures in lab/seq/normal.csv with header step,healthy_output_shape -- for example 'four replies, under 5 ms' rather than the literal text.
  4. Write lab/seq/failures.csv with header step,if_it_failed_here,rules_out stating what a failure at each step would mean.
  5. Write lab/seq/who.md recording the answer to 'who else is affected' for your own network today, and why that question belongs before step one.

Verify

ls lab/seq/step-*.txt | wc -l
awk -F, 'NR>1 && NF>=4 {n++} END {print n" step(s) with both columns"}' lab/seq/proved.csv
awk -F, 'NR>1 && NF>=2 {n++} END {print n" healthy signature(s)"}' lab/seq/normal.csv
awk -F, 'NR>1 && NF>=3 {n++} END {print n" failure meaning(s)"}' lab/seq/failures.csv
grep -c . lab/seq/who.md

Six or more captures, six or more steps with both what-it-proved and what-it-did-not filled, healthy signatures recorded, failure meanings for each step, and the scoping note. The what_it_did_not column is the one that matters: a successful ping proves reachability and says nothing about the service.

Notes

Capture the healthy output. Half of diagnosis is recognising that something is not normal, and that requires having looked at normal on purpose at least once.

This is an independent study companion for CompTIA A+ Core 1 220-1201 and is not produced by or endorsed by CompTIA.