DNS Propagation: Why Your Domain Change Isn't Live Yet
Why DNS changes take minutes or days to go live, how TTL actually controls it, and how to check propagation status globally when a launch depends on it.
Prerequisites
- A domain where you've recently changed a DNS record
- Omnvert DNS Propagation Checker
Step-by-step
- 1
What propagation actually means
DNS changes don't travel instantly. They spread through a global network of recursive resolvers, each caching answers for a set duration (TTL). 'Propagation' is the time it takes for the old cached value to expire on every resolver that matters and for the new value to be served from authoritative nameservers through each of them. There's no central switch to flip — it's a patchwork of independent caches.
- 2
TTL is the number that controls everything
TTL (Time To Live) is set per DNS record and tells resolvers how long to cache before asking again. TTL 300 (5 min) → changes propagate in ~10–30 minutes globally. TTL 3600 (1 hour) → ~2–6 hours. TTL 86400 (24 hours) → 24–48 hours. The pro move: lower TTL to 300 before a planned change, wait for the old TTL to expire, then make the change. Propagation after that feels almost instant.
- 3
Why you see the new record but your colleague doesn't
Different locations resolve through different recursive resolvers — ISP resolvers, 8.8.8.8, 1.1.1.1, corporate DNS, each with its own cache. Your resolver may have already fetched the new record while your colleague's ISP still holds the old one with minutes or hours left on its TTL. This is normal, not a bug; propagation is never instant across every network on Earth at the same second.
- 4
Check propagation with Omnvert
Open the DNS Propagation Checker, enter your domain, pick the record type (A, AAAA, CNAME, MX, TXT, NS), and run the check. The tool queries resolvers from multiple global locations simultaneously. Green = new value served; red or orange = still old. Locations still old are where propagation hasn't completed yet.
- 5
What to do if propagation is stuck
Verify you saved the record correctly at your registrar or DNS provider — double‑check the value field and the record type. Confirm you edited the right zone (www vs root domain). Flush your local DNS cache: Windows 'ipconfig /flushdns', Mac 'sudo dscacheutil -flushcache', Linux 'sudo systemd-resolve --flush-caches' (or 'sudo resolvectl flush-caches' on newer systemd). Then wait — if the old TTL was high before your change, there's no shortcut past it.
- 6
MX records — special care during migrations
Changing MX records affects mail delivery. During propagation, some senders will deliver to the old MX and some to the new — depending on whose resolver cached what. Keep the old mail server receiving during the transition, and don't delete the old MX record or disable the old mailbox until the propagation check shows every resolver resolving the new value. Losing an inbound email during a cutover is the kind of bug that shows up in customer support three days later.
The 'propagation complete' moment is when ALL major resolvers return the new value. Run the Omnvert DNS tool across 10+ locations — if every row is green, you're safe to remove the old record.