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I've decided to downgrade my hosted server since migrated my eCommerce website to Shopify.

Nothing important is actually hosted on the server. The only critical thing would be the domain DNS records pointing to the Shopify site.

Due to the server downgrade I will be switching from one dedicated IP address to another dedicated IP address. Will that cause any effects with DNS?

Edit: for more context the current A DNS record of mydomain.example directly to Shopify's IP address.

I do see that there are some names like cpanel.mydomain.example which do have an A record of my IP address - I assume I would need to change these to the new IP address?

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    DNS was designed to allow IP address changes!
    – MSalters
    Apr 14, 2022 at 19:14

3 Answers 3

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No matter what you do, you can't 100% control clients cache and hence some will continue to use the old IP address for "some" time.

Which means, your service needs to continue to exist to the old address for "some" time. How long? In theory, the delay of your current TTL on A record, but it is never a problem to wait more than that and it is strongly recommended (if you are into scheduled planned changes, you can plan for proper cool off periods to transition smoothly).

If you ensure both IP addresses work during the transition, you avoid lots of problems.

For a quicker transition, you can at the DNS level:

  • lower the current TTL value on the A record (anywhere your old IP address appear), without going lower than 300 or so
  • from the moment you see the change live on all authoritative nameservers, wait for the previous TTL time
  • now, normally, all clients asking for the IP address get it with the new reduced TTL but still with old IP address, that is the expected goal there
  • do your zone content change to use the new IP address
  • from the moment you see the change live on all authoritative nameservers, wait for the current TTL time before even thinking about shutting down the traffic reaching the old IP address.
  • at the end you can change again the TTL to some higher values (consult your DNS provider and webhosting company); anything around a couple of hours/a couple of days is pretty standard (and contrary to popular belief just using the lowest possible one is not always a good idea and never without drawbacks: high TTLs help you battle against DoS or other problems on the DNS servers)
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Further to Patrick's answer, in cpanel, if you have access to WHM you can go to

Home > Account Functions > Change Site’s IP Address and choose the site.

This will update the IP address of all DNS records that are set to the default IP address.

If you don't have WHM access, your hosting provider should be able to do that for you. It is a trivial task.

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Useful stuff from Patrick however the service will still be offline for some users for a while. This is avoidable, but not when you are using the unprefixed domain as the DNS name for the site. If your DNS name was www.mydomain.example then you could have multiple addresses concurrently (and potentially multiple instances running concurrently). But my domain.example can only be a single A record.

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