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GitHub Pages Tools

Free DNS Record Quick Reference

Enter your domain and get a quick-reference table of common DNS record types with example values for that domain. Covers A, AAAA, CNAME, MX, and TXT records with practical setup notes for each type.

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What is DNS Record Quick Reference?

DNS records translate human-readable domain names into the instructions that route traffic, deliver email, and verify domain ownership. Beginners encounter A, AAAA, CNAME, MX, and TXT records most often when setting up custom domains for hosting services such as GitHub Pages. Each record type serves a different purpose: A records point to IPv4 addresses, AAAA records point to IPv6 addresses, CNAME records alias one name to another, MX records direct email, and TXT records hold verification and policy data. This tool provides example values and setup context without requiring command-line knowledge.

quickAnswer

DNS records connect your domain to hosting services by mapping names to IP addresses, mail servers, and verification data. Each record type serves a specific purpose and the wrong type can break your site or email.

Last updated: 2026-06-11

limitations

  • The generated example records are generic. Actual DNS values depend on your hosting provider, email service, and specific requirements.
  • DNS changes can take from minutes to several hours to propagate globally depending on TTL values and the domain provider.
  • A CNAME record cannot coexist with other record types at the same name. Using a CNAME at the apex will break other services such as email.

Sources:MDN Web Docs · W3C Specifications · jquery.app on GitHub

How to use this tool

  1. Enter your domain name. The tool generates example DNS records based on common hosting scenarios.
  2. Review the generated table of record types, each with an example value and a short explanation.
  3. Read the setup notes under each record type for practical configuration guidance.
  4. Use the examples as a starting point for your actual DNS configuration at your domain provider.

What you can use it for

  • Set up a custom domain for GitHub Pages by adding the correct A or CNAME records at your domain registrar.
  • Configure email delivery for a domain by adding MX records pointing to your email provider.
  • Add domain verification TXT records required by Google Search Console, GitHub Pages, or third-party services.

Use cases

Practical examples

example

www subdomain with CNAME

A site owner wants www.example.com to load a GitHub Pages site. The tool generates a CNAME record pointing www.example.com to your-username.github.io.

example

Apex domain with A records

A publisher wants example.com without www. The tool lists the GitHub Pages A record IP addresses and explains that a CNAME cannot be used at the root of a domain.

Common mistakes

  • Confusing CNAME and A records and using a CNAME where an A record is needed or vice versa.
  • Adding a CNAME at the apex or root of a domain, which is not allowed by the DNS specification.
  • Forgetting to set TTL values, leaving the default TTL which may be longer than intended for change management.

verification

  1. Use a DNS lookup tool such as dig or a web-based DNS checker to confirm each record resolves to the expected value after propagation.
  2. Verify the site loads over HTTPS after DNS changes are complete. Some DNS providers may cache stale records longer than the configured TTL.

FAQ

Questions about DNS Record Quick Reference

What is the difference between an A record and a CNAME?

An A record maps a domain name directly to an IPv4 address. A CNAME maps one domain name to another domain name, which is then resolved through additional DNS lookups.

Can I use a CNAME at the root domain?

No. The DNS specification does not allow a CNAME at the apex of a domain. Use A records for the root domain or check whether your DNS provider offers a CNAME flattening or ALIAS feature.

What TTL value should I use?

Use 300 or 600 seconds during initial DNS setup so changes propagate quickly. Switch to 3600 or higher after everything is working to reduce DNS query load.

How do I verify that DNS changes have fully propagated?

Use a tool like dig, nslookup, or an online DNS checker to query your domain against multiple public resolvers. Check that all resolvers return the new record values. Propagation timing depends on the TTL: a record with a TTL of 3600 seconds can take up to an hour for all caches to expire. Reduce the TTL to 300 before making a planned change, then raise it after confirming the change is live.

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