Online Tool Store
CNAME Chain Checker
Follow a CNAME chain hop by hop to its final A or AAAA record, and flag loops, excessive hops, and the apex-CNAME problem.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Network
CNAME Chain Checker
Frontend preview — no upload or external service.
Chain trace
www.example.com → app.provider.net → lb-eu.provider.net → 203.0.113.42. Three hops, no loop, total added lookup latency around 40 ms.
How the CNAME Chain Checker works
- Enter the hostname you want to trace.
- Read every hop; each one is an extra DNS lookup before the connection can start.
- Check the final record actually resolves — a chain ending in a name with no A record fails in a way that looks like a server problem.
The method
A CNAME points one name at another, and the resolver must look up each name in turn until it reaches an address record.
every hop is an additional round trip before the first byte of the connection
Three hops on a cold cache can add tens of milliseconds to a first request, which is why providers offer CNAME flattening at the apex.
FAQ
How many CNAME hops are too many?
More than two or three is worth questioning. Each hop costs a lookup, and long chains usually mean a vendor pointing at a vendor pointing at a vendor — with each one able to break your site.
Why can't a CNAME sit at the domain apex?
Because the apex must carry SOA and NS records, and a CNAME cannot coexist with other records for the same name. Providers offer ALIAS or flattening as a workaround, but it is a provider feature, not standard DNS.
What causes a CNAME loop?
Two names pointing at each other, usually after a migration where one side was updated and the other was not. Resolvers detect it and fail, which presents as an unresolvable host.
How we compare
| Feature | Online Tool Store | A terminal utility | A hosted diagnostics service |
|---|---|---|---|
| Every hop shown | ✓ | Manual | Yes |
| Loop detection | ✓ | ✓ | ✓ |
| No terminal needed | ✓ | ✗ | ✗ |
| Explains apex restriction | ✓ | ✗ | ✗ |
CNAME Chain Checker counts the hops, because each one is both a latency cost and another vendor who can take your hostname down.