Compare DNS responses of different resolvers

What does DNS propagation mean?

After a change, resolvers can provide even older responses from their cache. At times, this leads to different results. The tool queries two public DNS services from the Seitenreport server and contrasts their responses. It does not operate measuring stations in different countries and does not map every Internet access.

Records and TTL separately assess

Select A, AAAA, CNAME, MX, NS, TXT, SOA or CAA. The output names found records including their remaining TTL. Different TTLs alone do not change the DNS content: A resolver may have queried the same entry earlier. TXT values are preserved in their spelling, while hostnames and IP addresses are normalized for comparison.

Deviating answers do not automatically mean an error

In addition to an ongoing transition, geo-DNS, load balancing and CDN configurations can cause different responses. Check if the displayed targets are part of your intended configuration. Equal responses from two services are a positive point of comparison, but not evidence of a completed global change.

NXDOMAIN, NODATA and non-testable

NXDOMAIN means that the requested DNS name does not exist according to the answer. NODATA refers to a successful request without entering the selected type. A time limit or SERVFAIL, on the other hand, is shown as non-auditable. From none of these answers a binding registration of the domain is derived.

Targeted verification after a change

First, compare the actually changed name and record type, such as the MX record of the main domain. For multiple names and a before/after comparison, use the DNS Moving Check. The queries run via documented DNS-over-HTTPS interfaces of Google and Cloudflares.

Frequent questions