DNS lookup

Check the CNAME record of a subdomain and where it points

A CNAME record makes one name an alias of another. The resolver follows the alias and returns the addresses of the target name.

What the CNAME record shows

CDNs, help desks and landing page builders ask you to point a subdomain at their host with a CNAME. A name with a CNAME cannot hold other records, so the root domain usually keeps A records and subdomains use CNAME.

The result shows the chain: the CNAME with its target first, then the records of the target. Each step of a long chain adds a lookup to the first connection.

When you need it

Check a subdomain after you connect it to a CDN or a SaaS service
Find the real host behind a tracking or landing domain
Spot a CNAME that still points at a service you have deleted

Questions about DNS records

01Can the root domain have a CNAME?

The DNS standard does not allow it, because the root must hold SOA and NS records. Some DNS providers offer ALIAS or CNAME flattening, which answers with A records instead.

02Why is there no CNAME in the result?

The name has its own A or AAAA records, so it is not an alias.

03What is a dangling CNAME?

A CNAME that points at a removed resource, such as a deleted storage bucket. Someone who registers that resource takes over your subdomain, so remove such records.

04Can a CNAME sit next to MX or TXT on the same name?

No. A CNAME replaces the whole name, so the name can hold no other records. If a subdomain needs mail or a verification TXT record, use an A record instead of the CNAME.

05Can I chain several CNAMEs?

You can, but each link adds a query for the resolver, and resolvers cut chains that run too long. Point the CNAME straight at the final name.