Dig DNS Investigation Tool Checklist for System Admins

halfbrain_logo512adminJune 18, 2026
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Dig DNS Investigation Tool Checklist for System Admins

dig helps system admins inspect DNS records directly. DNS issues can make a healthy server look broken, especially during domain migration, Cloudflare setup, SSL issuance or server IP changes.

Core principle

DNS answers the question: where should this name go? Before debugging Nginx or WordPress, prove that the domain resolves to the expected place.

Checklist

  1. Check A record for root domain.
  2. Check www record.
  3. Check nameservers.
  4. Check CNAME records if used.
  5. Query multiple public resolvers.
  6. Check TTL when planning migration.
  7. Compare DNS result with VPS IP.
  8. Check whether Cloudflare proxy changes visible IP.
  9. Test DNS before SSL issuance.
  10. Document authoritative DNS provider.

Reusable lesson

dig applies to website migrations, SSL errors, CDN setup, email records, API subdomains, staging environments and cloud architecture troubleshooting.

Checklist Type Troubleshooting
Level Beginner
Risk Level Medium Risk
Estimated Time 20–45 minutes

When to Use This Checklist

Use this checklist when debugging domain pointing, DNS propagation, SSL issuance, Cloudflare behavior or website migration problems.

Required Tools

Terminal access, dig, domain name, expected VPS IP, DNS provider access, Cloudflare access if used

Before You Start

Know which DNS provider is authoritative before editing records. Editing the wrong DNS panel changes nothing.

Structured Checklist Steps

  1. Check root A record.
  2. Check www record.
  3. Check nameservers.
  4. Check CNAME.
  5. Query Google DNS.
  6. Query Cloudflare DNS.
  7. Compare with VPS IP.
  8. Review TTL.
  9. Check proxy behavior.
  10. Document DNS owner.

Verification Steps

  1. Domain resolves to expected target.
  2. Nameservers are correct.
  3. www behavior is understood.
  4. TTL is known.
  5. DNS layer is confirmed before server debugging.
See also  Curl HTTP Debugging Tool Checklist for System Admins

Rollback Plan

If DNS points to the wrong IP, restore or update the record at the authoritative DNS provider and avoid unrelated server changes while propagation completes.

Common Mistakes

  • Editing DNS at the wrong provider.
  • Testing only one resolver.
  • Confusing Cloudflare proxy IP with origin IP.
  • Installing SSL before DNS is correct.
  • Ignoring www records.

Related Commands

dig example.com
dig www.example.com
dig NS example.com
dig @8.8.8.8 example.com
dig @1.1.1.1 example.com
dig CNAME www.example.com

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Disclaimer: The guides, checklists, commands, and examples on HalfBrain.net are provided for educational and operational reference only. Server environments, hosting providers, software versions, security settings, and WordPress configurations can vary, so you should always review commands before running them on your own system. We do our best to keep the content accurate and useful, but we cannot guarantee that every command, configuration, or recommendation will fit every environment. Always back up your website, database, and server configuration before making changes. HalfBrain.net is not responsible for data loss, downtime, security incidents, misconfiguration, or other issues that may result from applying the information on this website. Use the material at your own discretion.

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HalfBrain.net is a practical field notebook for people who want to self-operate websites, VPS servers, Linux systems, Docker stacks, Nginx configurations, DNS records, SSL certificates, and AI automation workflows. Our goal is simple: turn messy infrastructure problems into clear, repeatable checklists, commands, and operating procedures. We focus on practical execution, not theory for theory’s sake.

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