TL;DR: "DNS propagation" is the delay between changing a DNS record and the whole internet seeing the new value. It happens because servers cache the old record until its TTL (time-to-live) expires. Most changes are live within minutes to a couple of hours. If you just added an SPF or DMARC record and it's "not working", it may simply not have propagated yet. Scan your domain to check whether the new record is live.
What's actually happening
DNS isn't one central database — it's cached copies all over the world. When you change a record, your authoritative server updates immediately, but resolvers elsewhere keep serving the cached old value until it expires. There's no "propagation wave" travelling the globe; it's just caches timing out at different moments.
TTL: the dial that controls it
Every record has a TTL in seconds — how long resolvers may cache it. A TTL of 3600 means up
to an hour of caching. Tip: before a planned change, lower the TTL (e.g. to 300) a day ahead, make the change, then
raise it again. New changes then propagate in minutes.
How long does it really take?
- Most records: minutes to a couple of hours.
- Worst case: up to 24–48 hours if the old TTL was long.
- Nameserver (NS) changes: can take longest, as they involve registry caches.
How to check if it's live
- Run a free scan — if your new SPF/DMARC/other record is detected, it's live for us.
- Query from a few networks (or use an online checker) — if some show the new value and some the old, it's still propagating.
- Give it the length of the old TTL before assuming something's wrong.
FAQ
Can I speed up propagation?
Not after the fact — but lowering the TTL before a change makes future updates fast. Once changed, you wait out the old TTL.
My record shows for me but not others — why?
Different resolvers cached the old value at different times. They'll catch up as their caches expire.
I added DMARC but DMARC still "fails" — propagation?
Possibly, if it's brand new. If it persists past the TTL, it's a configuration issue — re-check the record itself.
Not sure if your new record is live yet? Scan your domain, then reply to your report — we're developers and we'll confirm it's correct and working.