Free tool
Find the canonical domain a hostname aliases to, resolved live from public DNS.
Enter a domain to look up its CNAME records.
A CNAME (Canonical Name) record makes one hostname an alias for another. For example, www.example.com might be a CNAME pointing at example.com, so both resolve to the same place.
CNAMEs are widely used to point subdomains at CDNs, SaaS platforms, and load balancers. This tool shows the canonical target a hostname aliases to.
A CNAME record maps one name to another name, never to an address:
www.example.com. 3600 IN CNAME example.com.
shop.example.com. 3600 IN CNAME stores.example.net.
The trailing dot marks a complete name. In a zone file, a target without it is read as relative to your own domain, so stores.example.net would become stores.example.net.example.com. Most web control panels handle this for you, but not all of them do.
The rule that catches people out: a name that has a CNAME cannot have any other record (RFC 1034). You cannot add an MX or a TXT verification record next to it, and you cannot put a CNAME on the bare domain, which must hold SOA and NS records. For the apex, DNS providers offer CNAME flattening or ALIAS and ANAME records, which they turn into ordinary A records before answering.
The tool asks for the CNAME of the exact name you enter and shows its target. A name can have only one CNAME, so a healthy result is a single row, with the record count and query time in the bar above. Lookups run live from the PulseStack™ server in the UK against Google Public DNS (8.8.8.8), with Cloudflare (1.1.1.1) as the fallback, and are not stored.
It shows one hop. If the target is itself an alias, look that name up next to follow the chain, or run the A record lookup on the original name to see the addresses at the end: resolvers follow the whole chain for you.
No CNAME records found is normal for the bare domain and for any name with its own A or AAAA records. If you expected an alias, check you entered the full name, such as www.example.com rather than example.com. To see every record a name has in one go, use the DNS lookup.
Other records at the same name. Adding a TXT or MX record to a name that already has a CNAME breaks the rule above. Many DNS providers refuse the change; where one accepts it, resolvers may give inconsistent answers. Put verification records on a different name, or replace the CNAME with A records.
Dangling CNAMEs. The record still points at a service you have cancelled, such as a deleted cloud storage bucket, app or hosted page. If someone else can claim that name on the same platform, they can publish content on your subdomain, which is known as subdomain takeover. Delete CNAMEs for services you no longer use.
Validation records removed. Some services check a CNAME again later. Managed certificate services, for example, may look for their validation CNAME at each renewal, so deleting it can make a renewal fail months afterwards.
A CNAME your dashboard shows but the lookup cannot see. If your DNS host proxies or flattens the record, as Cloudflare does for proxied records and at the apex, public resolvers receive the provider's addresses instead of the CNAME, so no CNAME appears here. That is how the feature works, not a fault.
On macOS or Linux, run dig CNAME www.example.com +short. On Windows, use nslookup -type=CNAME www.example.com, or in PowerShell Resolve-DnsName -Name www.example.com -Type CNAME.
A plain dig www.example.com shows the full picture: every CNAME in the chain followed by the final A records, all in the answer section.
To keep an eye on an alias, a PulseStack™ DNS record monitor on a paid plan checks the CNAME as often as every five minutes and alerts you when it no longer contains the target you expect. The DNS monitoring best practices guide covers which records are worth watching.
Standard DNS does not allow a CNAME on the root (apex) domain, because a CNAME cannot share its name with any other record and the apex must carry SOA and NS records. Many providers offer CNAME flattening or ALIAS/ANAME records as a workaround.
An A record points to an IP address directly. A CNAME points to another hostname, which is then resolved to find the IP. CNAMEs are useful when the target IP may change, since you only update it in one place.
Most hostnames resolve directly through A or AAAA records and have no CNAME, and the bare domain normally has none. A CNAME only appears when the exact name you entered is an alias for another name.
No. RFC 2181 says MX and NS records must point to a hostname that has its own address records, not to an alias. Some mail servers tolerate it, but others refuse, so point MX records at the mail server's real hostname.
Yes. Resolvers follow the chain to the end, but every hop adds a lookup and one more record that can change without you knowing. Keep chains as short as you can.
Every one runs a real check, live, with nothing to install.
PulseStack™ DNS record monitors check CNAME, A, AAAA, MX, TXT and NS records as often as every five minutes and alert you when the value you expect disappears. Included from the Starter plan at £9 a month, with a 14-day trial and no card.