Free CNAME lookup

This free CNAME lookup shows where an alias really leads. Enter a hostname and you see the canonical name target that DNS publishes for it, together with the TTL. Custom domains on landing-page builders, help desks, shops, email tools and CDNs almost always depend on a CNAME, and when one of those integrations stops working, the alias is the first thing worth verifying.

How does the CNAME lookup work?

You enter a hostname and run the check. The tool asks DNS specifically for the CNAME record of that name and prints the canonical name target plus the TTL. Unlike an A record lookup, which would quietly follow the alias and show you the final IP, this query tells you which name the alias hands over to – the detail you need when a provider asks you to “point your subdomain to” one of their hostnames.

If the answer is empty, the name has no alias: it either carries its own A/AAAA records or does not exist in the zone. Both cases are worth knowing when an integration’s setup screen keeps saying “DNS not detected”.

What is a CNAME record?

A CNAME record – canonical name – maps one hostname to another hostname. It says: “this name is just another name for that one; ask about that one instead”. A resolver that hits a CNAME restarts its search with the target and eventually returns the target’s addresses.

example.com.        A      203.0.113.10
www.example.com.    CNAME  example.com.
shop.example.com.   CNAME  stores.shop-platform.example.
go.example.com.     CNAME  pages.landing-builder.example.

The appeal is delegation. When shop.example.com is a CNAME of a store platform’s hostname, the platform can move its servers, change IPs or add regions without you ever touching your DNS. That is why SaaS tools, CDNs, help centres, status or landing pages and email-tracking domains almost always ask for a CNAME rather than an IP address.

When should you check a CNAME record?

CNAMEs fail in quiet ways: the record exists, it just points somewhere slightly wrong. A lookup turns a vague “the custom domain doesn’t work” into a concrete comparison with the value the provider expects.

• You are connecting a custom domain to a SaaS tool – landing pages, email tools, help centres, shops.
• You changed CDN, reverse proxy or app hosting and the old target may still be in place.
• A subdomain loads the wrong content, a default provider page or shows a DNS error.
• You are verifying DNS changes during a migration between DNS providers.
• You are cleaning up and want to find aliases that point at services you no longer use.

CNAME vs A vs AAAA

A CNAME is an alias from one hostname to another. An A record points a name directly to an IPv4 address, an AAAA record to an IPv6 address. You use a CNAME when someone else controls the destination and might change its IPs; you use A/AAAA when you control the server and its address is stable.

Why a CNAME cannot coexist with A, MX, TXT or NS records

A CNAME declares that the name is an alias – that all of its data lives under the target. Allowing an MX or TXT record on the same name would contradict that, so the DNS standard forbids it. Many DNS panels refuse to save the combination; others accept it and resolvers then behave unpredictably.

In practice this rule bites in two places. First, you cannot add a TXT verification record to a name that is already a CNAME; put the TXT on a different label if the provider allows it. Second, you cannot put a CNAME on the root domain, because the apex must carry SOA and NS records.

CNAME at the root domain: ALIAS, ANAME and CNAME flattening

Because example.com itself must hold SOA and NS records, a standard CNAME there is impossible. Many DNS providers work around this with a provider-specific record often called ALIAS or ANAME, or with “CNAME flattening”: you configure the root as if it were an alias, and the provider resolves the target behind the scenes and answers with plain A/AAAA records.

Flattening keeps the convenience of an alias while staying standards-compliant, and it saves visitors an extra lookup. The trade-off is that a lookup of the root domain shows ordinary IP addresses, not the target name – the alias exists only inside your provider’s system. If your provider offers neither feature, point the root to fixed IPs with A/AAAA and make www the CNAME.

CNAME vs 301/302 redirect

A CNAME works at the DNS level: it decides which server a name resolves to, and the browser’s address bar keeps showing your hostname. A 301 or 302 redirect is an HTTP response from a web server that tells the browser to load a different URL, and the address bar changes. They solve different problems and are often used together – for example, www as a CNAME that reaches the same server, which then redirects to the root domain.

A CNAME cannot move visitors from one URL to another, and it passes no SEO signals. If you want old.example.com to send people to new.example.com, you need a redirect on a web server that answers for the old name.

Does a CNAME automatically show the same website?

Not necessarily. A CNAME only makes DNS return the same IP addresses as the target. The browser then connects and sends your hostname in the Host header – and the server decides what to show for that name. If the platform behind the alias has not been told about your custom domain, you get a default page, a “domain not found” message or a certificate error.

That is why SaaS setups always have two halves: create the CNAME at your DNS provider, and add the same hostname in the service’s dashboard so it can route requests and issue a certificate. A lookup confirms the first half; the provider’s status screen confirms the second.

CNAME chains and dangling aliases

A CNAME may point to another CNAME, and providers often build such chains internally. Short chains work, but each hop is an extra lookup, a bit of latency and another place where something can break; very long chains or loops make resolution fail entirely. Keep your own aliases one hop deep where you can.

Watch out for dangling CNAMEs as well: aliases that still point to a SaaS hostname after you cancelled the account. If someone else can claim that hostname at the provider, they can serve content under your subdomain – a known takeover risk. Removing aliases for services you no longer use closes that door.

CNAMEs and monitordefend

This lookup checks an alias once. monitordefend does not monitor DNS records, but if a website you add to it stops loading because an alias broke, the five-minute uptime check confirms the outage with a second attempt and sends you an email.

Frequently asked questions

Can I use a CNAME for the root domain (apex) like example.com?

Not with standard DNS, because the apex must hold SOA and NS records and a CNAME cannot coexist with other data. Use your DNS provider’s ALIAS/ANAME record or CNAME flattening, or point the root to IP addresses with A/AAAA records.

Why can’t a CNAME exist together with A, MX, TXT or NS records?

A CNAME declares the hostname an alias of another name, so resolvers look up everything at the target. Additional records on the same name would contradict that, which is why the standard forbids the combination.

CNAME vs 301/302 redirect: what’s the difference?

A CNAME is a DNS alias that changes where a name resolves; the URL in the browser stays the same. A redirect is an HTTP response that sends the browser to a different URL, so the address bar changes.

If I point a CNAME to another domain, will it show the same website?

Not always. The CNAME only leads DNS to the same IP addresses. What visitors see depends on whether the web server or platform there is configured for your hostname.

Can a CNAME point directly to an IP address?

No. A CNAME target must be a hostname. To point a name at an IP address, use an A record for IPv4 or an AAAA record for IPv6.

Are CNAME-to-CNAME chains OK?

They usually work, but each hop adds a lookup and another chance for errors such as loops. Keep chains short and avoid stacking aliases you control on top of each other.

What is CNAME flattening?

A DNS provider feature that resolves a CNAME target internally and answers with the final A/AAAA records. It enables alias-like behaviour on the root domain and saves resolvers an extra lookup.

Related pages

• Free A record lookup
• Free AAAA record lookup
• Free nameserver lookup
• Redirect checker
• DNS checker
• DNS monitoring: protect your website from DNS changes and outages