Lower the DNS TTL an hour before you move a site

What the TTL decides

Every DNS answer carries a TTL, the number of seconds a resolver may keep it. Most panels write 3600. After you change an A record, some visitors keep reaching the old server for up to that hour.

For a site with a database, that hour is where data gets lost. An order placed on the old server never reaches the new one.

The order that keeps the switch short

1. Copy the site to the new server while the old one keeps serving.
2. Lower the TTL on every record you will change to 60 seconds.
3. Wait for the old TTL to run out. With 3600, wait one full hour.
4. Run the final sync of files and databases.
5. Change the records straight after the sync.

Lowering the TTL changes nothing for visitors. It only shortens how long the next change takes to arrive.

What it looked like on 11 domains

On 25 October we moved 11 domains off a DirectAdmin server. Their zones had a TTL of 3600. We lowered it to 60 at 20:50 UTC and switched at 21:53.

Within a minute, public resolvers in eight countries returned the new address. The last database copy ran seconds before the switch, so nothing written on the old server was left behind.

Have HTTPS ready before you switch

A new server cannot get a Let's Encrypt certificate until the domain points at it. That gap breaks HTTPS for every visitor who arrives first.

Copy the current certificate and key across, and install them before the switch. KLYRN refuses a certificate that misses a name the site answers on, such as www. Then it requests its own once DNS has moved.

Two checks people skip

Compare the copy against the original before you switch. Request each site from both servers with a fixed address and compare the status code and page title.

Look for suspended accounts. Four of our accounts were suspended for unpaid bills on the old server. Moving them as active would have put them back online, so they were suspended on the new one first.