First, the key terms.

Resolver
A service that looks up DNS answers for a client.
TTL
A record’s time-to-live, which guides how long an answer can be cached.

The idea, explained

A domain is not the same as the website’s content or hosting account. DNS records direct clients toward services; A and AAAA records carry addresses, while a CNAME creates an alias. Resolvers cache answers according to record lifetimes, so changes may not appear everywhere immediately. HTTPS certificates establish a separate part of the connection’s identity. Correct DNS is necessary for many services but does not prove that the application is working.

STEP 1

Separate the name from the service

Registering a domain gives control of a name under the registrar’s rules. It does not create a website, email inbox or application database. Those are separate services that DNS records help clients locate.

STEP 2

Understand record purposes

An address record directs a name toward an IP address; an alias record points one name toward another name. Mail-related records serve different purposes. Changing a website’s record should not require deleting unrelated records that keep email working.

STEP 3

Allow for caching and other layers

Resolvers reuse answers for a period. A change can therefore be visible to one visitor before another. Even after resolution is correct, certificate setup and application routing must work. Test these layers independently when troubleshooting.

Follow a worked example.

A school moves its website to a new host and updates its DNS record. Some visitors still reach the old address while a cached answer remains valid. The email service can stay elsewhere because it uses different records.

Walk it through, one step at a time

  1. A fictional school moves its website from host A to host B and verifies that B serves the correct site.
  2. It updates the required DNS record, leaving its mail records unchanged. Some visitors may briefly use cached answers for A.
  3. After the relevant caches expire, visitors should resolve toward B, but they can still encounter an application error if B is misconfigured.

Where people get stuck

Changing a domain record does not copy application files, migrate a database or repair an expired certificate.

Now try it yourself.

Pause before opening each answer. Explain your reasoning in your own words.

1. Check the core idea

Can a domain resolve successfully while its website returns an error?

Reveal the answer & reasoning

Yes. Name resolution and application processing are different stages. The address can be correct while the service is unavailable.

2. Apply what you learned

Why should you avoid deleting all DNS records to fix a website problem?

Reveal the answer & reasoning

Other records may be necessary for email, authentication or domain verification. Identify the specific incorrect record and preserve unrelated services.