A/AAAA or CNAME?

In D(omain) N(ame) S(ystem) settings CNAME refers to a domain name.
There are aspects to using CNAME that can improve your knowledge:

  • ‘example.com CNAME www.example.com’ is blocked by my hosting provider. This does not fit with their earnings model. A / AAAA is a general way out here.
  • CNAME requires slightly more search time; security tests are more complicated; a low security risk is mentioned.
  • When using A / AAAA you can inconsistently refer to IPs / servers with or without www..
  • ‘www.example.com CNAME example.com’ replaces an early, not really safe, ‘Force Redirect’ in the DirectAdmin control panel.
  • For incoming e-mail in MX settings, ‘mail.example.com’ is more stable than ‘example.com’. In case of relocation of the website, the e-mail traffic is not affected. E-mail client Outlook also defaults with ‘mail.example.com’.
  • Proper use of CNAME for DMARC at rijksoverheid.nl, see dnsspy.io. The false alarm in this tool has been addressed.