CNAME Lookup
Look up the CNAME record of a subdomain and follow the chain of aliases to the address it ends at. Handy for CDN, SaaS and ESP setups (www, shop, DKIM selectors).
What the CNAME Lookup shows
A CNAME (canonical name) record makes one name an alias of another: www.example.com points at example.netlify.app, and the resolver looks up that name instead. Hosting platforms, CDNs and email providers hand out CNAME targets so they can move their servers without asking you to change DNS.
The lookup reads the CNAME of the name you enter, then follows the chain hop by hop - up to 8 - until a name with an address, and shows the IPs it ends at. A chain that loops or ends without an address is flagged: the second is how subdomain takeovers start.
Other single-record lookups: TXT Lookup, A Record Lookup, SRV Lookup, MX Lookup. Paste any record into the DNS Record Explainer for a plain-English breakdown.
Frequently asked questions
How do I find the CNAME record of a subdomain?
Enter the full subdomain above, for example www.example.com or shop.example.com. The lookup shows the alias target and follows it to the final address. From a terminal: dig CNAME www.example.com @1.1.1.1 or nslookup -type=CNAME www.example.com.
Why is there no CNAME on my root domain?
The DNS standard does not allow it: the root (example.com) must carry SOA and NS records, and a CNAME may not share a name with any other record. Point the root at an A record, or use your DNS host's flattening (Cloudflare CNAME flattening, Route 53 alias, ALIAS/ANAME), and keep the CNAME on www.
What is the difference between a CNAME and an A record?
An A record maps a name straight to an IPv4 address. A CNAME maps a name to another name, whose address is then looked up. Use a CNAME when a provider owns the address and may change it; use an A record when you control the IP.
Why do email providers ask for CNAME records?
SendGrid, Mailchimp, Amazon SES and others publish your DKIM keys on their side and ask you to CNAME selector._domainkey.yourdomain to them, so they can rotate keys without your help. Check the selector name here, then confirm the key with the DKIM Checker.
What is a dangling CNAME?
A CNAME that still points at a deleted resource - a Heroku app, an S3 bucket, a GitHub Pages site. Anyone who claims that resource on the provider takes over your subdomain. Remove CNAMEs to services you no longer use; the Takeover Checker scans a whole domain for them.