Inventory the current setup
Before changing DNS, record the current A, AAAA, CNAME, NS, MX, TXT and CAA values, TTLs, redirects, certificates, mail providers and third-party senders. Export or screenshot the old configuration so you can compare and roll back.
Prepare the new service before cutover
Build and test the new website, application, database, certificates, redirects and mail service while the old system remains live. Test the new origin directly where authorized, but do not publish DNS until the new service is ready.
Lower TTL ahead of time
Lower the TTL of records you plan to change before the migration, while the old service is healthy. Existing cached answers cannot be shortened after the fact, so allow the previous TTL window to pass before the cutover.
Switch web records deliberately
Change the A and AAAA records, or the relevant CNAME, to the new service. Check that IPv4 and IPv6 both work, the certificate covers the hostname, redirects are correct and the application serves the expected content. Do not change unrelated records in the same step.
Protect email continuity
Keep MX records pointing to a working mail service until the new mail system is ready. Recreate required SPF, DKIM selector and DMARC records, verify every legitimate sender and check the Authentication-Results header on test messages. Web migration does not automatically migrate email.
Verify from multiple viewpoints
Use DNS Lookup to compare answers from more than one resolver or network. Use Website Diagnostics for HTTPS status, response time, final URL and headers, and use IP Lookup to confirm the new network and ASN when relevant. Expect different answers while old caches expire.
Keep the old service during the overlap
Do not shut down the old web or mail service immediately after changing DNS. Keep it available for at least the relevant cache window and monitor requests, logs, mail queues and error rates. This gives you time to identify clients using stale records.
Rollback safely
If the new service fails, restore the recorded old DNS values, keep the old service healthy and wait for caches to converge. A rollback is not instant when resolvers still hold the new answer, so plan for both states and avoid repeated DNS changes.
Restore normal TTL and document the change
After the new website and mail flow are stable across networks, raise TTL to a sensible value. Record the final DNS values, certificate renewal ownership, mail authentication settings, monitoring checks and the time the old service can be retired.
Check real data now
Use the live IIPP tool to inspect the domain or IP address you are working with.
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