Technical operations
Technical operations
This domain tests whether you can run a web property reliably: DNS and TLS, caching and CDN behavior, deployment and rollback, monitoring, backup and recovery, and routine security hygiene. The exam favors operational reasoning over tool-specific trivia.
Core rules
- Know DNS record roles: A/AAAA for addresses, CNAME for aliases, MX for mail, TXT for verification and policy.
- Track TLS certificate expiry and chain completeness; redirect HTTP to HTTPS and consider HSTS after validation.
- Cache deliberately: long-lived immutable assets with hashed filenames, short or revalidated HTML.
- Deploy through a pipeline with staging, automated checks, and a tested rollback path.
- Monitor uptime, synthetic journeys, real-user metrics, logs, and alerts; test restores, not just backups.
- Apply least privilege, patch dependencies, and set security headers such as CSP and X-Content-Type-Options.
Worked example
After a release, some users see stale CSS while others see new styling. The likely cause is HTML cached too long or assets served without versioned URLs. The fix is to fingerprint asset filenames, set Cache-Control: public, max-age=31536000, immutable for those files, and keep HTML at a short max-age or require revalidation. Reasoning: versioned URLs make new assets unique, so long caching is safe, while HTML must point to the current asset set. A rollback plan and staging check prevent repeat incidents.
Traps
- Caching HTML for a year, then wondering why content is stale.
- Forgetting certificate renewal or missing intermediate certificates.
- Raising DNS TTL just before a migration instead of lowering it.
- Logging personal data or secrets in plain text.
- Treating an untested backup as a recovery plan.