Chapter 14 — Network and communications security: automation | Technical Network and communications security

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Chapter 14 — Network and communications security: automation

Lesson map

Lesson 14 published. Map, example, EX053.

flowchart TD
  N0["Learning outcomes"]
  N1["14.1 Choosing what to automate"]
  N2["14.2 Building safely"]
  N3["14.3 Reviewing output"]
  N4["14.4 Keeping automation healthy"]
  N5["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5
  N5 --> EX["Worked example"]
  EX --> Q["Exercise EX053"]

Logical drawing

flowchart LR
  N0["Learning outcomes"]
  N1["14.1 Choosing what to automate"]
  N2["14.2 Building safely"]
  N3["14.3 Reviewing output"]
  N4["14.4 Keeping automation healthy"]
  N5["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5 --> Q["EX053"]

[Learning outcomes]
    |
    v
[14.1 Choosing what to automate]
    |
    v
[14.2 Building safely]
    |
    v
[14.3 Reviewing output]
    |
    v
[14.4 Keeping automation healthy]
    |
    v
[Synthesis]
    |
    v
[Worked example] --> [Exercise EX053]

Learning outcomes

You will (1) automate routine checks; (2) protect automation credentials; (3) review automated output.

14.1 Choosing what to automate

Amina automates tasks that are repetitive and clearly defined: nightly configuration exports from switches and firewalls, the weekly certificate expiry report, the weekly VPN failure summary and the hourly check that each device is sending logs. These tasks need no judgement and produce output that is easy to review. She avoids automating changes to live devices, since a mistaken automated change could affect both offices at once, and Castleford has no out-of-hours staff to notice quickly. Each automated task replaces a manual one Rosa used to do.

14.2 Building safely

The scripts run on a small management server in the management zone. They use read-only accounts on devices, so even if the scripts were misused they could not change configurations. Credentials are stored in the operating system's protected store, not in the scripts. Each run is logged, and failures send an email to Rosa. The scripts are version-controlled and tested in the lab first. Automation runs with real access, so it must be built as carefully as any other system component.

14.3 Reviewing output

Automation produces reports, but people must read them. Amina designs reports to be short: a list of items needing action, with everything else summarised in one line. Rosa reviews them each Monday as part of a thirty-minute routine. If a report is too long or full of noise, it will be ignored, so Amina adjusts thresholds after the first month based on Rosa's feedback. Useful automation saves time only if its output leads to action. Rosa marks each item as done or deferred.

14.4 Keeping automation healthy

Scripts break when devices are upgraded or formats change. Amina adds a check that each script ran and produced plausible output, such as at least one line per device. She documents each script's purpose, inputs, outputs and owner. When she finishes her placement, Rosa and the support company can maintain them. Automation that only its author understands becomes a hidden dependency that fails silently after the author leaves. After every device upgrade, the scripts are run once by hand and their output compared with the previous week to confirm formats have not changed.

Worked example

Four tasks are automated with read-only accounts; Monday reviews take thirty minutes.

Synthetic case. Automation is synthetic.

Errors and limits

Automated reports that are too long are skipped and miss real problems.

Exercises

EX053 — Automation choice. Why avoid automating changes to live devices? Rubric: 3 = mistakes could affect both offices; no out-of-hours staff;; 2 = risk;; 1 = slow;; 0 = none.
EX054 — Credential storage. Where are automation credentials stored? Rubric: 3 = OS protected store, not scripts;; 2 = protected store;; 1 = in script;; 0 = none.
EX055 — Report design. How are automated reports kept useful? Rubric: 3 = short, action items first, tuned with feedback;; 2 = short;; 1 = long;; 0 = none.
EX056 — Script health check. How does Amina detect a broken script? Rubric: 3 = check it ran and produced plausible output;; 2 = check;; 1 = vague;; 0 = none.

Synthesis

Carefully built, read-only automation with short reports saves time and catches problems early.

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