Dns Propagation Isn T Real

"DNS propagation" isn't real.

I know. You've been told to "wait for DNS to propagate" your whole career, but that's not what's actually happening.

Here's what's really going on.

DNS doesn't push. It pulls.

When you update a DNS record, nothing gets sent out to the internet. There's no broadcast, no sync, no propagation wave rolling across the globe.

Instead, DNS is a caching system. Resolvers only fetch records when someone asks for them, and then they hold onto that answer until the TTL expires.

TTL is the whole game.

TTL (time to live) is a number in seconds attached to every DNS record. It tells resolvers "you can cache this answer for this long."

If your TTL is 86400 (24 hours), and someone looked up your domain an hour before you made a change, their resolver won't check again for another 23 hours.

So it's not propagation. It's cache expiration.

Why does it work for some people and not others?

When you make a DNS change and your coworker sees it immediately but you don't, it's because their resolver either had an expired cache or had never looked it up before. Your resolver still has the old answer cached.

Different ISPs, different resolvers, different cache states.

The practical takeaway: Before making a DNS change, check your current TTL. If it's high, lower it to 300 (5 minutes) and wait for the old TTL to expire. Then make your change. You just eliminated your "propagation" delay.

DNS isn't magic. It's just caching all the way down.

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