Security administration · Lesson 14 of 35 · 10 minutes

Final incident review

Pull together logs, firewall state, and a final review note.

Open the lab Course map

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learner@clairos:~ $

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Your objectives

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1
Filter denied journal
Run journalctl -u ssh | grep refused.
Hint & worked example
Read the training journal by unit or a bounded line window. Select input lines that match a pattern; -i ignores case, -n adds line numbers, and -v inverts selection.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
journalctl -u ssh | grep refused
```
Remember: A relevant unit and time range are more useful than an unfiltered wall of logs. No matches is exit status 1, which is different from a malformed invocation.
2
Check firewall
Run ufw status.
Hint & worked example
Inspect or adjust the training firewall rule list. No real firewall changes occur.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
ufw status
```
Remember: Firewall rules should be scoped and reviewed; simulator access is not a production change approval.
3
Write final review
Run echo final-review > final-incident-review.txt.
Hint & worked example
Write simple text to standard output. Prefer printf when exact formatting matters.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
echo final-review > final-incident-review.txt
```
Remember: Redirection can overwrite an existing file before the command runs.

Understand the pattern

Security administration is a repeatable evidence workflow.

journalctl: Read the training journal by unit or a bounded line window.
A relevant unit and time range are more useful than an unfiltered wall of logs.
grep: Select input lines that match a pattern; -i ignores case, -n adds line numbers, and -v inverts selection.
No matches is exit status 1, which is different from a malformed invocation.
ufw: Inspect or adjust the training firewall rule list. No real firewall changes occur.
Firewall rules should be scoped and reviewed; simulator access is not a production change approval.
echo: Write simple text to standard output. Prefer printf when exact formatting matters.
Redirection can overwrite an existing file before the command runs.

Worked example and expected result

$ journalctl -u ssh | grep refused

May 26 08:18:33 clairos-learn sshd[118]: password authentication refused
May 26 08:21:44 clairos-learn sshd[141]: root login refused by policy

Exit status: 0. The command completed successfully in the training fixture.

$ ufw status

Status: active
- allow 22/tcp
- allow 80/tcp
- allow 443/tcp
- deny 23/tcp

Exit status: 0. The command completed successfully in the training fixture.

$ echo final-review > final-incident-review.txt

(no output; exit 0)

Exit status: 0. The command completed successfully in the training fixture.

Try a variation

Repeat this workflow in the sandbox with a different scratch filename. Keep the system fixtures unchanged and compare the observed output with your expectation before moving on.

Explain it

In “Final incident review”, which interpretation is safe?A command appearing in history proves it completed successfully.A successful first check guarantees that every dependent service is healthy.Firewall rules should be scoped and reviewed; simulator access is not a production change approval.

Apply it elsewhere

Before adapting the ufw workflow from “Final incident review” to another server, what should you do?Skip output inspection whenever the command is familiar.Confirm the current directory, target identity, permissions, and the installed command behavior first.Paste the training paths unchanged into production.

Keep the momentum.

Complete the lab, then explain and apply the pattern.

Next: SSH dry run Try an incident drill

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