FIELD GUIDE/Domains & DNS

What should I check before changing DNS records?

DNS changes are easy to make and slow to reverse. Before touching any record, it's worth understanding what the existing records do — because some of them may be doing more than you expect.

DNS changes are not just website changes

When someone says they need to update DNS, they usually mean they want to point the domain to a new website or hosting provider. That's a legitimate reason to change DNS. But DNS records control more than the website — they also govern where email is delivered, how outgoing messages are authenticated, and a range of third-party services that may have added their own records over time. Changing one record without understanding what else is in the zone can break things that had nothing to do with the original task.

Start by exporting everything that's currently there

Before making any change, log in to wherever the domain's DNS is currently managed — the registrar, a hosting provider, or a dedicated DNS service — and document every record that exists. Most DNS management interfaces have an export function; if not, take a full screenshot or copy the records manually. The goal is a complete picture of the current state before anything is touched. This takes a few minutes and makes every subsequent decision easier.

Website records

The records that point the domain to a website are typically A records (which map the domain to an IP address) or CNAME records (which point one domain name to another). These are usually what the new hosting provider's instructions are asking you to change. They're also the records most likely to be replaced correctly, because the instructions are written specifically for this purpose. The risk is not usually in the website records themselves — it's in what else gets changed or deleted in the process.

Email records — the most common casualty

Email delivery depends on MX records, which tell the internet which mail servers should receive messages sent to your domain. If MX records are removed or overwritten during a DNS change, incoming email stops arriving. Depending on how the change was made, messages may bounce back to senders or disappear entirely. MX records should never be changed unless you are deliberately moving to a new email provider — and even then, the new records should be in place before the old ones are removed.

Supporting email records — SPF, DKIM, and DMARC — are separate TXT records that help receiving mail servers verify that messages from your domain are legitimate. These are easy to overlook because they don't affect whether email arrives; they affect whether it's trusted. If they're lost during a DNS change, outgoing email may start landing in spam filters, sometimes days after the change when the effects propagate.

TXT records used for verification

Many third-party services add TXT records to a domain as a way of verifying ownership. Google Search Console, Google Workspace, Microsoft 365, and various security and marketing platforms all use this mechanism. These records don't do anything visible day-to-day — they just sit in the DNS zone confirming that the domain owner authorized the service. If they're deleted, the verification lapses, and the service may lose its connection to the domain. Restoring verification usually requires going back through the setup process for each affected service.

CNAMEs and other service dependencies

CNAME records are used for a wide range of purposes beyond the main website: subdomains for specific services (mail.example.com, app.example.com, calendar.example.com), third-party platform integrations, and custom domains for hosted tools. Before changing or removing a CNAME, it's worth understanding what it points to and whether anything depends on it. A CNAME that looks unfamiliar may be supporting a service that someone in the organization uses regularly.

If you're moving DNS to a new provider entirely

Migrating a DNS zone — moving all records from one provider to another — requires recreating every existing record at the new provider before the migration is completed. The new provider's nameservers should be serving all the correct records before the domain is pointed at them. If the migration is done by simply switching nameservers without recreating the records, everything that depended on the old DNS — email, verifications, subdomains — stops working the moment the switch propagates.

If you're not certain which records are safe to change, or if the DNS zone contains records you don't recognize, that's the right moment to stop and get help. A DNS mistake that breaks email can take hours to propagate a fix, and messages sent during that window may be lost permanently. Web Relevant can review an existing DNS zone, identify what each record does, and help plan a change that doesn't break anything in the process.