--- title: Free CNAME Lookup description: See where a hostname is aliased — the canonical name it resolves to once every CNAME in the chain is followed. Verify a CDN or SaaS custom-domain setup and spot an alias that still points at a service you stopped using. canonical: https://watchfor.io/cname-lookup --- [Back to all free tools](/free-tools) # CNAME Lookup See where a hostname is aliased — the canonical name it resolves to once every CNAME in the chain is followed. Verify a CDN or SaaS custom-domain setup and spot an alias that still points at a service you stopped using. [How to use this tool](/blog/how-to-check-a-cname-record) Result No result yet Fill in the form above and run it — the result appears here. Monitor this 24/7 — get alerted when a failure is confirmed. [Start free](/auth/sign-up) Only run these tools against systems you own or are authorized to test. Using them to scan or probe systems without permission violates our [Terms](/legal/terms). ## What is CNAME Lookup ? A CNAME record says "this name is an alias for that name": www.example.com → example.com , shop.example.com → shops.myshopify.com , cdn.example.com → d111111abcdef8.cloudfront.net . Resolvers follow the alias and return whatever records the target has. It is how you hand a subdomain to a SaaS product or a CDN without ever knowing their IP addresses — and how a subdomain silently keeps pointing at a service you cancelled two years ago. This tool follows a name's CNAME chain and shows the canonical name at the end of it — where the alias finally lands. It shows that one name, not each link in between, and for a name that isn't an alias it returns the name itself. Pair it with an A lookup to check the end of the chain still resolves: a target that no longer resolves is a dangling CNAME, which is both a broken subdomain and a subdomain-takeover risk. ## How it works What the lookup does with an alias: - 1 Follow the aliases — The resolver follows the CNAME for the name, and the target's CNAME if it has one, until it reaches a name with real records. A name that is not an alias comes back as itself — it holds its A/AAAA/MX records directly. - 2 Show where it ends — The canonical name at the end of the chain. For a one-link alias that is the CNAME target; for a longer chain the links in between aren't listed ( dig prints each one). TTLs aren't shown. - 3 Confirm the end of the chain resolves — Follow up with an A or AAAA lookup of the same name to see the addresses it finally resolves to, and to catch a target that no longer exists. A CNAME cannot coexist with other records on the same name (RFC 1034). That is why the apex, which must hold SOA and NS records, cannot be a CNAME. ## When you'd use it ### Verifying a SaaS custom domain Shopify, HubSpot, Netlify, GitHub Pages, Zendesk — they all ask for a CNAME to their name. When their dashboard says "DNS not configured", look the CNAME up: it's missing, points at the wrong target, has a typo, or is still cached from before you added it. ### "The certificate is for another site" A subdomain aliased to a provider that hasn't been told about your hostname serves its default certificate. The CNAME is right; the provider-side configuration isn't. The lookup confirms which is which. ### Hunting dangling records Old staging. , demo. and blog. names pointing at services that were cancelled. If the target name is now unregistered or claimable, an attacker can host content under your subdomain. Look up each CNAME and check that its target still resolves to something you control. ### Understanding why a record "won't save" The DNS provider refuses a CNAME on example.com or refuses to add a TXT next to an existing CNAME. Both are the spec, not the provider: use ALIAS/ANAME on the apex, and put TXT records on a name that isn't an alias. ## Reading the result ### Canonical name Where the alias chain ends. Note the trailing dot in raw DNS output — shops.myshopify.com. is fully qualified; without it, some tools append your own zone and produce shops.myshopify.com.example.com . ### The name you typed, returned as is The name is not a CNAME: it holds its records directly. An A lookup shows what they are. ### Chain length One CNAME is normal; two happen with CDNs in front of SaaS; more than that adds a lookup per link and is a sign something can be simplified. dig shows how many links there are. ### NXDOMAIN Nothing resolved: the name doesn't exist, or the chain ends at a target that doesn't. Clients get an error; the subdomain is effectively dead and, if the target is claimable, dangerous. dig CNAME on the name shows the first link even when its target is gone. ## Check it yourself dig CNAME www.example.com @1.1.1.1 +noall +answer dig www.example.com +short follows the chain and prints each link on its own line, ending with the addresses. ## Common pitfalls ### CNAME at the apex example.com cannot be a CNAME because it must carry SOA and NS records. Use your provider's ALIAS / ANAME / CNAME-flattening feature, which answers with A records on the apex while following a target name behind the scenes. ### MX pointing at a CNAME Mail servers must be named by A/AAAA records, not aliases (RFC 2181). Some MTAs tolerate it; others refuse to deliver. Point MX at the real hostname. ### TXT verification on an aliased name You can't add a TXT record on a name that is a CNAME. Providers that ask for both a CNAME and a TXT on the same name expect the TXT on a different label ( _verification.www ) — read their instructions carefully. ## Run CNAME Lookup on every change, not just once. Get alerted when an outage is confirmed — across HTTP, DNS, SSL, RDAP, ping, blacklist and more. Free forever for 15 monitors. No card. [Start free](/auth/sign-up) ## Frequently asked questions What's the difference between a CNAME and an A record? An A record points at an IP address; a CNAME points at another name and inherits whatever that name resolves to. Use CNAME when someone else controls the addresses (CDN, SaaS); use A when you do. What's the difference between CNAME and ALIAS/ANAME? ALIAS (also ANAME, or CNAME flattening) is a provider feature, not a DNS record type: the provider resolves the target itself and answers with A/AAAA records, so it works at the apex and alongside other records. Clients never see a CNAME. Why does the CNAME target have a trailing dot? In zone files a trailing dot marks a fully qualified name. Without it the name is relative to the zone, which is how cdn.provider.net accidentally becomes cdn.provider.net.example.com . Can I chain CNAMEs? Yes — resolvers follow chains, typically up to 8–16 links. Each link is an extra lookup on a cold cache, so keep chains short. How long does a CNAME change take to propagate? Up to the old record's TTL, like any record. Caches also hold the target's records with their own TTL, so a target change can take the longer of the two. ## Related dns tools - [DNS LookupResolve A, AAAA, MX, TXT, NS, SOA, CNAME, PTR, CAA, SRV records for any domain.](/dns-checker) - [DNS PropagationCheck how a DNS record looks from every prober region simultaneously — spot stale anycast nodes and propagation gaps on a world map — plus an A+ to F DNS health grade for the zone: nameservers, delegation, DNSSEC and CAA.](/dns-propagation-checker) - [Whois LookupModern RDAP-based domain registration lookup: registrar, expiry, nameservers, status flags.](/whois-lookup) - [DNS Health CheckerGrade a domain's DNS A+ to F: how many nameservers it has and on which networks, lame delegation, whether the registry and the zone agree, SOA serials, DNSSEC and CAA, with the fix for every problem. Then see what every probe location answers, on a map.](/dns-health-checker) --- Canonical page: https://watchfor.io/cname-lookup · Site guide: https://watchfor.io/llms.txt