isitdns?

Resolver comparison: one name, four resolvers

resolver comparison

Do the big public resolvers give this name the same answer, and which one differs?

isitdns.net/#dig: the same question over DoT, Do53 over TCP and UDP, IPv6, or at any public resolver address.

read
  • GO with all four selected, the closing line reads same answer at cloudflare, google, quad9, adguard; a single-resolver run is one row, with nothing to compare it to. TTLs differ by row by design: each cache counts its own copy down (RFC 1035 section 3.2.1).
  • NO GO one row differs in rcode, or its data comes with an EDE line: read that line (RFC 8914). A filtering resolver answers NXDOMAIN or 0.0.0.0 with EDE 17 (RFC 8914 section 4.18) -> you: ask an unfiltered resolver, or the zone's own servers: nameserver consistency.
  • NOT RUN rows that differ in data with the same rcode and no EDE line: a name a CDN steers by location answers each resolver's location with its own set, and this read cannot tell steering from an old copy. The TTL counting down at each row says the cache is live; what the zone's own servers hold is nameserver consistency.
example

example.com A, read 2026-10-18T22:02:05Z:

  isitdns · dig · example.com A
  ;; asked 2026-10-18T22:02:05.419Z over DoH (dnssec on) from the Cloudflare edge, not your network

  ;; @cloudflare (cloudflare-dns.com) over DoH · 8 ms · 179 bytes · NOERROR · flags: qr rd ra ad
  ;; asked 2026-10-18T22:02:05.419Z from the Cloudflare edge (IAD), remote address unavailable from this vantage
  ;; ANSWER (3)
  example.com.                     300  IN  A      104.20.23.154
  example.com.                     300  IN  A      172.66.147.243
  example.com.                     300  IN  RRSIG  A 13 2 300 20261019230205 20261017210205 34505 example.com. T1Ly4qTm5shO5THTJUTIQHBDVgLZwO1oA2WyExngg+9RUhIfsGP6fqUpBwHGTYhIxH/BMQlFW96HBM9Zw1NWhw==  ; key tag 34505, inside its window, expires 24 h after this read (the signature itself is not checked here)
  ;; EDE: none received

  ;; @google (dns.google) over DoH · 31 ms · 179 bytes · NOERROR · flags: qr rd ra ad
  ;; asked 2026-10-18T22:02:05.419Z from the Cloudflare edge (IAD), remote address unavailable from this vantage
  ;; ANSWER (3)
  example.com.                     300  IN  A      172.66.147.243
  example.com.                     300  IN  A      104.20.23.154
  example.com.                     300  IN  RRSIG  A 13 2 300 20261019230205 20261017210205 34505 example.com. GseV3CD2m6hPi2f9nIBsjY2tAXlKL+WcmWR52/q49CODwpyAk8Y157lH10apQsct9dnaDfeg6kq0i9/dCLmB4g==  ; key tag 34505, inside its window, expires 24 h after this read (the signature itself is not checked here)
  ;; EDE: none received

  ;; @quad9 (dns.quad9.net) over DoH · 19 ms · 179 bytes · NOERROR · flags: qr rd ra ad
  ;; asked 2026-10-18T22:02:05.419Z from the Cloudflare edge (IAD), remote address unavailable from this vantage
  ;; ANSWER (3)
  example.com.                     161  IN  A      104.20.23.154
  example.com.                     161  IN  A      172.66.147.243
  example.com.                     161  IN  RRSIG  A 13 2 300 20261019225946 20261017205946 34505 example.com. Q0GkpAN2fhWJGs3vmLNFS9U4vrmiIaDN/bKfqeO5I/6xBLgTUeGIaLiRVIbWtuKoaGobpaYdP5GuDDjxKYCb7Q==  ; key tag 34505, inside its window, expires 24 h after this read (the signature itself is not checked here)
  ;; EDE: none received

  ;; @adguard (dns.adguard-dns.com) over DoH · 104 ms · 179 bytes · NOERROR · flags: qr rd ra ad
  ;; asked 2026-10-18T22:02:05.419Z from the Cloudflare edge (IAD), remote address unavailable from this vantage
  ;; ANSWER (3)
  example.com.                     300  IN  A      104.20.23.154
  example.com.                     300  IN  A      172.66.147.243
  example.com.                     300  IN  RRSIG  A 13 2 300 20261019230205 20261017210205 34505 example.com. T37J3XTeT9ju32dpVFkWtgzFK2LtEg+FN/nwCMQBvljOmJqsIqNfGVEXDyxtlDyCmIVzK08n9wk5ppiX4jBr5w==  ; key tag 34505, inside its window, expires 24 h after this read (the signature itself is not checked here)
  ;; EDE: none received

  ;; same answer at cloudflare, google, quad9, adguard: NOERROR, A 104.20.23.154 172.66.147.243, AD 4 of 4

  ;; TTL of example.com A: 161 s at quad9 to 300 s at adguard across 4 rows with the same data

  browser: https://isitdns.net/dig?name=example.com&type=A&resolver=all
from your own machine
dig @1.1.1.1 example.com A
dig @8.8.8.8 example.com A
dig @9.9.9.9 example.com A
dig @94.140.14.14 example.com A

The same four from your own path, over port 53: a difference from the readings above is something to compare, resolver by resolver.

the manual
other jobs