Global DNS
propagation check.

What is DNS propagation?

When you change a DNS record — updating your A record, switching nameservers, or adding a CAA record — the change has to ripple out to every DNS resolver on the internet. Resolvers cache records to be fast, and each one holds its cache for as long as the record's TTL says. Propagation is the time between you publishing the change at your authoritative nameservers and every cache around the world catching up.

Why does it matter?

Until propagation completes, different visitors hit different versions of your site. New customers in Singapore might land on the old IP for 12 hours after your team in Dar es Salaam already sees the new one. Email can bounce. Certificates can fail to validate. SEO crawlers can see one record while your visitors see another. This tool lets you watch the wave from 10 different vantage points at once.

How long does propagation take?

Cleanly: as long as the previous record's TTL. If you had a 3600 s (1 hour) TTL, full propagation takes at most one hour. Most consumer ISPs respect TTL. Some override it to a minimum of a few hours regardless. The Big resolvers (Google, Cloudflare) typically update within minutes for changes — that's why they appear first in our list.

Tanzania-specific note

For .tz domains, propagation depends on TZNIC's authoritative servers reflecting the change first, then every recursive resolver pulling the new record. Updates at TZNIC are near-instant for changes pushed via EPP — what you usually see lagging is the resolver layer, not TZNIC itself.