Unless you have full control over your server and the routers it is connected to, you will probably have to change the DNS for your site as part of the migration. Most people don’t need to think about DNS all the time, because it’s one of those things that you set up once, and it rarely gets modified after that time.
If that’s you, never fear! This page is here to help remind you!
DNS stands for Domain Name Server (or Service) and translates a human readable name (like domain.com) into a routable IP address (like 123.45.67.89).It doesn’t matter what kind of server OS, webserver application, TLD (top-level domain), registrar, host, or file format you are using. All browsers look up DNS the same way. Anything else you can think of that does the same thing?
That’s right, the phone book!
DNS is just like the phone book for the Internet, no matter what kind of phone or provider you use, or whether you are a business or a household; as long as you are listed, people will be able to call you.
I won’t berail you with an advanced explanation beyond this here; there are already a wealth of guides on the Internet that will tell you everything you need to know about DNS.
Where does this come in with relation to migrations?
Like I mentioned a bit earlier, unless you have full control over the routing to your source and target servers (i.e. you are your web host), its very unlikely you will be able to keep your original IP addresses as part of the migration, so DNS updates are a must. Specifically, any references to your old server’s IP that relate to the services and websites you are moving should be updated to the new server’s IP. This is likely just A records, but could also be TXT records (for SPF, if you are hosting mail alongside your website) or SRV records.
As part of your migration plan, figure out where your DNS is located (the linux dig and whois commands are very useful here) and ensure that you have sufficient access to update the records at those nameservers, whether they are custom nameservers on your source server or another server, hosted by your registrar or current host, or at a third party like Cloudflare.
