Most migration outages are DNS mistakes: a forgotten MX or TXT record, a long TTL, or a DNSSEC DS record left at the registrar. This checklist orders the steps so the old and new hosts overlap and nothing breaks, with DomainOps checks at each stage.
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A week before
Export or screenshot every record at the current DNS host. Run the DNS lookup "all records" view as a second copy.
Note every TXT record (verification tokens), MX, SPF includes and DKIM selectors.
Lower TTLs on records that will change to 300 seconds, and wait for the old TTL to expire.
Moving the website only
Set up the site on the new host and test it with a hosts-file entry.
Change the A/AAAA (or CNAME) records at your DNS host.
Watch Resolver compare until Google and Cloudflare both return the new address.
Keep the old host running for at least the old TTL, then a day more.
Moving DNS to a new provider
Recreate every record at the new provider first, and compare them record by record.
If DNSSEC is on, remove the DS record at the registrar and wait 24-48 hours before switching.
Change the nameservers at the registrar. The parent zone's NS TTL is often two days.
Check the NS lookup and the Registration tab both show the new nameservers, then re-enable DNSSEC.
After the move
Run the health report: address, MX, SPF, DMARC and DNSSEC should all pass.
Check the certificate on both the bare domain and www.
Raise TTLs back to 3600 or more once everything is stable.
Check each step with the tools below.
Website migration DNS checklist: questions and answers
How long does DNS propagation take?
As long as the TTL of the record that changed, everywhere that cached it. With a 300-second TTL, most users see the change within minutes. Nameserver changes depend on the TLD's NS TTL, commonly 24-48 hours.
Will email stop during a migration?
Only if MX or SPF changes. If you move the website only, leave MX, SPF, DKIM and DMARC untouched and email is unaffected.
Start from what you are doing
I am launching a new website
Check the domain resolves on both the bare name and www, the certificate covers both, and email is not left open to spoofing.
AltFTool does not store the domains or addresses you check. DNS lookups in the DNS, compare, email and IP tools run from your browser; registration, report and certificate checks pass through AltFTool's server and keep nothing.