DNS Checker

DNS propagation is the time between a record change and resolvers around the world serving the new value. A location row stands in for one resolver region. This board shows that layout without querying those resolvers.

A real propagation check asks several recursive resolvers and compares answers. Here the city list is fixed and the success bit is a coin flip. Use the board to learn the columns, then query resolvers if a DNS change is in flight.

City list is one of the values DNS Checker puts on screen. A propagation view pretends each row is a resolver in a city. The fixture lists New York, San Francisco, Toronto, London, Frankfurt, Paris, Mumbai, Singapore, Sydney, Tokyo, São Paulo, and Johannesburg. Those cities were not queried. The provider names Google DNS, Cloudflare, OpenDNS, and Quad9 are labels.

Read Propagated mark on its own before you mix it with the other rows. Propagated means that resolver already has the new value. Each city is marked success about 85 percent of the time and failed otherwise. Click again and a city can flip. Your DNS change did not reach it and then leave.

A and AAAA values answers a narrower question than the headline number. Address answers are what most people wait on after an origin change. A propagated A row shows 192.0.2.1. AAAA shows 2001:db8:85a3::8a2e:370:7334. Both are documentation ranges, not your new origin.

Treat MX, NS, TXT, CNAME as a label with a specific job. Other types carry mail, delegation, text, or an alias. MX is 10 mail.example.com, NS is ns1.cloudflare.com, TXT is an SPF sample, and CNAME is the domain you typed. Those strings are selected from the type, not returned by Quad9 or anyone else.

The Summary fraction line is worth a full stop. A board often says how many locations succeeded. The fraction is the count of random successes over 12. A high fraction is not evidence the world has your new record.

Record types you can pick include A, AAAA, CNAME, MX, NS, and TXT. Changing the type changes the sample value, not a live answer. Pending rows have an empty value. That emptiness is the failed coin flip, not a resolver timeout.

If you remember one sequence from DNS Checker, remember the fields in the order they change a decision. City list matters because A propagation view pretends each row is a resolver in a city. In practice, The fixture lists New York, San Francisco, Toronto, London, Frankfurt, Paris, Mumbai, Singapore, Sydney, Tokyo, São Paulo, and Johannesburg. The mistake to avoid is this: Those cities were not queried. The provider names Google DNS, Cloudflare, OpenDNS, and Quad9 are labels. Propagated mark matters because Propagated means that resolver already has the new value. In practice, Each city is marked success about 85 percent of the time and failed otherwise. The mistake to avoid is this: Click again and a city can flip. Your DNS change did not reach it and then leave. A and AAAA values matters because Address answers are what most people wait on after an origin change. In practice, A propagated A row shows 192.0.2.1. AAAA shows 2001:db8:85a3::8a2e:370:7334. The mistake to avoid is this: Both are documentation ranges, not your new origin. MX, NS, TXT, CNAME matters because Other types carry mail, delegation, text, or an alias. In practice, MX is 10 mail.example.com, NS is ns1.cloudflare.com, TXT is an SPF sample, and CNAME is the domain you typed. The mistake to avoid is this: Those strings are selected from the type, not returned by Quad9 or anyone else. Summary fraction matters because A board often says how many locations succeeded. In practice, The fraction is the count of random successes over 12. The mistake to avoid is this: A high fraction is not evidence the world has your new record. After that, the checks are simple. You ran the board twice and saw a city flip. You did not treat 192.0.2.1 as the origin. You did not wait on a city name to turn green. You read provider names as labels. Real resolvers are the source if a DNS change is in progress.

Keep DNS Checker as this step only. When the job moves on, the Domain to IP is the next page: Domain to IP takes one or more domain names and shows an IPv4 address and a hosting name beside each. The Domain Age Checker covers a different piece of the same work: Domain Age Checker takes a domain and shows an age in years, a created year, and an expiry date.