About cname lookup
A CNAME record makes one name an alias of another. For example, www.example.com can point to example.com or to a hosting provider.
Rules
- A name with a CNAME cannot have other records such as MX or TXT.
- The root of a domain usually cannot be a CNAME, so providers offer ALIAS or ANAME records.
A worked example
www.example.com may be a CNAME for example.github.io if the site is hosted on GitHub Pages. The lookup shows the target name, and you can then look up that name's A records to find the final address.
Common issues
- A CNAME on the root domain breaks other records. Use an A record or an ALIAS record.
- A typo in the target gives an error page.
- Too many chained CNAMEs slow down lookups.
Checking the chain
After finding the CNAME, look up the target's A record to see the final IP address. If the target does not resolve, the alias is broken and visitors will see an error.
