What this checks
Enter a hostname and this tool asks DNS for its CNAME record, then follows the alias as far as it goes and lists the full chain in resolution order. A CNAME (canonical name) record is an alias: it says "this name is really that name," and the resolver restarts the lookup at the target. Add an expected target in the optional field and the tool also generates step-by-step instructions for adding that CNAME at your DNS provider, detected from the domain's nameservers.
An empty result means no CNAME was found for the name — but note it cannot tell a genuine "no CNAME exists" apart from a temporary resolver hiccup, so it reports only what it found, never a definitive absence.
CNAME chains
A CNAME can point at a name that is itself a CNAME, forming a chain:
shop.example.com → stores.myplatform.com → lb.myplatform.net,
and only that last name carries the actual A record. Chains are normal — SaaS and CDN providers use
them to keep an extra layer of indirection they can re-point without touching your DNS. But each hop
is another lookup and another thing that can break, so a chain that's several links deep is worth
understanding. This tool shows every hop so you can see exactly where a name ultimately lands.
The apex-CNAME problem
You cannot put a CNAME on the apex of a domain — the bare example.com with no
subdomain in front. The DNS rules forbid a CNAME from coexisting with the other records an apex must
have (NS and SOA), so most providers simply reject it. This is why setup guides tell you to point
www (a subdomain, where CNAMEs are fine) at your provider while the apex needs a
different approach — an A record, or one of the workarounds below.
ALIAS / ANAME flattening
To get CNAME-like behaviour at the apex, many DNS providers offer ALIAS or ANAME records (sometimes called CNAME flattening). These look like a CNAME to you — you enter a target hostname — but the provider resolves that hostname to its IP addresses behind the scenes and answers apex queries with plain A records, satisfying the rules. The catch is that it's a provider-specific feature under a provider-specific name, and it isn't a standard record type you'll see in a raw lookup. If your host offers it, it's usually the cleanest way to point an apex at a SaaS target.
FAQ
Why can't I put a CNAME on my root domain?
Because a CNAME can't coexist with the NS and SOA records every apex is required to have, and the DNS
standard forbids mixing them. Providers therefore block a CNAME at the apex. Use a subdomain like
www for CNAMEs, and an A record or an ALIAS/ANAME record for the bare domain.
What's a CNAME chain?
A chain is when a CNAME points at another name that is itself a CNAME, so the resolver follows several hops before reaching a name with an actual IP address. Chains are common with layered SaaS and CDN setups. Each hop is an extra lookup, so this tool lists every link so you can see where the name finally resolves.
CNAME vs. ALIAS?
A CNAME is a standard record type that works on subdomains but not the apex. An ALIAS (or ANAME) is a provider-specific feature that gives you CNAME-like targeting at the apex by resolving the target to IPs and answering with A records. Functionally similar for you to set up; different mechanisms underneath, and only ALIAS/ANAME is allowed at the root.
How long until a changed CNAME takes effect?
As long as the record's TTL, roughly. Resolvers that cached the old CNAME keep serving it until that cache entry expires, so a record with a one-hour TTL can take up to an hour to fully cut over. Lower the TTL a day before a planned change to shorten the wait.