DNS TTL Explained Before a Hosting Migration

DNS plays an important role when moving a website from one hosting server to another.

One DNS setting that website owners often hear about during migration is TTL.

Understanding TTL can make a hosting migration easier to plan.

What Is TTL?

TTL stands for Time To Live.

For DNS, TTL tells caching systems how long a DNS record can be cached before it should be queried again.

TTL is normally expressed in seconds.

Why Does TTL Matter During Migration?

When you change a DNS record, not every visitor necessarily sees the new value immediately.

Some DNS resolvers may continue using a cached value until the previous TTL period expires.

This is why DNS changes can appear gradual.

Lower TTL Before Migration

If you know a migration is coming, you may lower the TTL of relevant DNS records before making the change.

This can reduce the time that old DNS information remains cached.

However, lowering TTL does not instantly update every resolver.

Change the Correct DNS Record

Different records control different services.

Common records include:

• A
• AAAA
• CNAME
• MX
• TXT

Do not change records without understanding what service they control.

Website Migration and Email Are Different

A website may use an A record while email may use MX records.

Changing website DNS does not automatically mean email should be moved.

This is especially important when migrating a website while keeping email on the existing service.

Check Existing DNS Before Migration

Record the important DNS settings before making changes.

Review:

• A records
• AAAA records
• CNAME records
• MX records
• TXT records
• SPF
• DKIM
• DMARC

Keep Email Authentication in Mind

If your domain uses email authentication records, do not accidentally remove them during a website migration.

Website migration and email migration are separate tasks.

Test the New Server Before DNS Changes

Where possible, test the new hosting environment before changing DNS.

Check:

• Website pages
• Database
• SSL
• Forms
• Login
• Application functionality

Update DNS When the New Website Is Ready

Once the new server is tested, update the relevant DNS record.

Avoid making unnecessary DNS changes.

Do Not Expect Instant Global Changes

DNS caching means different users may temporarily reach different servers.

This is normal during migration.

Monitor Both Servers

During the transition, keep the old hosting environment available until you are confident that traffic has moved to the new server.

Restore TTL After Migration

Once the migration is complete and stable, you can increase TTL again if appropriate.

Higher TTL values can reduce repeated DNS lookups.

Check the Website From Different Networks

After DNS changes, test the website using different networks or DNS resolvers where possible.

This can help identify propagation differences.

Final Thoughts

TTL is an important part of DNS planning, but it is only one part of a successful hosting migration.

Record existing DNS settings, lower TTL in advance when appropriate, test the new server, update only the required records, and monitor the transition.

THE HOSTGURU customers planning a hosting migration should treat DNS and email configuration as separate items in the migration checklist.

Frequently Asked Questions