DNS Cache Checker

Every public resolver keeps a DNS cache — a short-lived copy of the answers it has already fetched from your authoritative nameservers. The record's TTL decides how long that copy is served before the resolver goes back to the source. Until it expires, visitors using that resolver see the cached value, not whatever you just published.

This tool queries each resolver directly and compares the remaining TTL it hands back against the authoritative TTL. A countdown lower than the authoritative value means the answer came from cache, and the difference tells you roughly how long it has been sitting there. Resolvers that return a different value than the authoritative answer are the ones still serving stale data.

Note that resolvers legitimately disagree for reasons other than lag. Geo-routed and anycast DNS hands different answers to different locations by design, so a mismatch is only a propagation problem when the cached value matches a record you previously published.