Host migrations break things quietly. The site looks fine on the new host, but the contact form stopped sending, the SSL certificate expired, email routing changed, or DNS records that were configured on the old host did not carry over. Here is what to check before and after the switch.
1. Lower your DNS TTL before you touch anything else
DNS records have a TTL (time to live) that tells resolvers how long to cache them. If your TTL is set to 86400 (24 hours), then after you change your DNS records, some visitors will still reach the old host for up to a day. Lower the TTL to 300 seconds (5 minutes) at least 24 to 48 hours before the migration. This way, when you do cut over, propagation happens in minutes instead of hours.
2. Export your full DNS zone file
Your current host or registrar has DNS records that may not be obvious: MX records for email routing, TXT records for SPF and DKIM, CNAME records for third-party services, A records pointing subdomains to specific servers. Export the entire zone file before changing anything. If you do not have it, you cannot rebuild it after the switch.
3. Check where email is routed
If your email runs through your hosting provider (common with cPanel hosts, GoDaddy, and similar), changing hosts will break email delivery. MX records need to point to wherever your email actually lives. If that is Google Workspace, the MX records point to Google. If that is the host itself, you need to set up email separately before cutting over.
Also verify that your SPF and DKIM records will still be valid after the migration. If the old host's IP addresses are in your SPF record and you are moving to a new host, your SPF record needs to be updated or your email will start failing authentication checks.
4. Verify SSL certificate provisioning
Most modern hosts provision SSL certificates automatically through Let's Encrypt. But the certificate on the old host does not transfer. After pointing DNS to the new host, the new certificate needs to be issued and verified. Until it is, visitors see a browser security warning. Check that the new host handles this automatically, or provision it manually before going live.
5. Test contact forms and integrations
Contact forms that use server-side email (PHP mail, SMTP through the host) will break on a new host with different mail configuration. Forms that submit to third-party services (Formspree, Zapier webhooks, API endpoints) should survive, but test every one. Also check booking widgets, payment integrations, and any embedded third-party service that might reference the old host's URL.
6. Keep the old host active after DNS changes
DNS propagation is not instant. If you lowered the TTL beforehand, most resolvers will pick up the change within minutes. But some will lag for hours, and edge cases can take up to 72 hours. Keep both hosts running for at least 24 to 48 hours and monitor traffic on both. Also verify that Google Search Console and any analytics tools are still receiving data from the new host.
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