What an MX record actually is
An MX record (short for Mail Exchanger record) is a line in your domain's DNS settings that tells the rest of the internet which server handles email for your domain. When someone sends a message to you@yourcompany.com, their email provider does not guess where to deliver it. It looks up the MX record for yourcompany.com and sends the message there.
Key takeaways
- An MX record tells the internet which mail server should receive email for your domain. Without one, or with one set up wrong, email for your company silently bounces or never arrives.
- MX records use a priority number, not a single address. Lower numbers are tried first, and a common mistake is getting that order backward or leaving an old provider's record in place.
- Checking and changing MX records does not require a developer. A DNS lookup takes seconds, and a domain platform that connects directly to your email provider can set the record automatically.
Every domain that receives email needs at least one MX record. Without one, mail addressed to your domain has nowhere to go, and it bounces back to the sender as undeliverable. This catches people off guard when they register a new domain, point the website at a host, and assume email will just work. Email delivery and website hosting are handled by completely separate DNS records, and setting up one does nothing for the other.
MX records are part of the same DNS system that handles domain-to-address lookups for websites, but they answer a different question. A DNS A record says where your website lives. An MX record says where your email lives. A company can, and often does, host its website with one provider and its email with a completely different one, purely because of how these records are configured.
How MX records work when someone emails you
Every MX record has two parts: a mail server address and a priority number. The priority number decides the order mail servers get tried in. Lower numbers go first.
A typical setup has more than one MX record for the same domain, usually a primary server at priority 10 and a backup at priority 20. If the primary server is unreachable, the sending mail server automatically retries the backup instead of giving up. This is why losing a single mail server does not usually mean losing email entirely, as long as the backup record is correct.
| Part | What it does | Example |
|---|---|---|
| Priority | Orders the servers to try, lowest first | 10 |
| Mail server | The actual server that accepts the mail | mail.yourprovider.com |
| TTL | How long other servers cache this record before checking again | 3600 seconds |
None of this happens instantly the first time you change a record. DNS changes propagate across the internet gradually, and a new MX record can take anywhere from a few minutes to 48 hours to be visible everywhere, depending on the TTL set on the old record. That is why MX changes should happen with the old record still working until the new one is confirmed live, not the other way around.
Common mistakes that break email delivery
MX records are simple in theory and easy to get wrong in practice. A handful of mistakes account for most email outages.
- Leaving the old provider's record in place. Migrating to a new email provider but forgetting to remove the old MX record means some mail keeps trying to reach a server that no longer exists.
- Getting the priority order backward. If the backup server is set to a lower priority number than the primary, mail routes to the backup first, and it may not be configured to accept it properly.
- Only one MX record with no backup. A single point of failure. If that one server has downtime, every incoming email bounces until it is fixed.
- Copying the wrong value from the provider's setup page. A single typo in the mail server hostname is enough to break delivery for the whole domain.
- Changing MX and email provider on the same day with no rollback plan. DNS propagation delay means some mail may still be routing through the old path for hours. Cutting the old server off too early loses that mail.
None of these mistakes are visible until someone notices email has stopped arriving, which is usually days after the change, not minutes. That delay is what makes MX record errors more costly than most DNS mistakes.
How to check your current MX records
Checking a domain's current MX records does not require special software or admin access. Any DNS lookup tool shows them in seconds, which is useful before making a change and for confirming a change actually took effect.
- Use a DNS lookup command. On Mac or Linux, running `dig MX yourdomain.com` in a terminal shows every MX record currently published for the domain, along with its priority.
- Or use a browser-based DNS checker. Free DNS lookup tools return the same information without needing a terminal, and most also flag obviously broken records.
- Compare against what your email provider expects. Your email provider's setup documentation lists the exact MX records it needs. If what is published does not match exactly, that mismatch is very likely why mail is not arriving.
- Check again after any change. DNS propagation means a change is not confirmed the moment you save it. Recheck a few hours later, and again the next day, before assuming a migration is complete.
Setting up or changing MX records the right way
The mechanics of adding an MX record are the same across most DNS providers: you enter a mail server hostname and a priority number in a form. The risk is not the form. It is doing this by hand across multiple domains, remembering to remove old records, and getting the priority order right every time.
- Get the exact values from your email provider first. Never guess a mail server hostname or priority. Your provider's documentation has the exact records it expects, and using anything else risks mail not being accepted.
- Add the new records without removing the old ones yet. Most DNS systems allow multiple MX records to exist during a transition. Add the new provider's records first.
- Confirm the new records are live and working, using a DNS lookup and a real test email, not just a saved settings page.
- Only then remove the old provider's records. Removing them too early, before the new setup is confirmed working, is how companies end up with a stretch where email silently fails.
- Document what changed and why, including the date, so the next person who touches this domain's DNS understands the current setup instead of guessing.
This is exactly the kind of task that benefits from a domain platform doing it for you rather than a person doing it by hand in a DNS control panel. WeldHost sets the correct MX record automatically the moment you connect a domain to WeldMail with one click, so there is no hostname to copy, no priority number to get backward, and no old record left behind by accident.
MX records when you switch domains or email providers
MX record changes usually happen for one of two reasons: switching email providers, or moving a domain to a new registrar or DNS host. Both carry the same risk, and both benefit from the same discipline: add before you remove, and confirm before you assume.
A domain transfer does not have to touch MX records at all if it is handled correctly, since a domain's registration and its DNS records are technically separate things. But in practice, a transfer is often the moment teams also decide to consolidate DNS management, so MX records do end up changing as part of the same project. Treat that as two separate changes, not one, even if they happen the same week.
Switching email providers is a bigger change, since it usually also means moving mailboxes and their contents, not just the DNS record pointing at them. The MX record change should be the last step, made once every mailbox is confirmed migrated and ready to receive mail at the new destination.
For a mid-market or enterprise team managing this across a handful of domains rather than one, doing it by hand multiplies the risk with every domain added. A platform where domains, DNS records, and email are managed in one place removes most of the manual copying that causes MX mistakes in the first place. WeldHost handles domain registration and DNS records, including MX, with one-click connection to WeldMail, as part of the WeldSuite complete software suite. That is $49 per user per month on the Business tier or $69 on Scale, with everything, including AI, included at every tier.
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Frequently asked questions
What is an MX record in simple terms?
An MX record is the DNS setting that tells other mail servers which server should receive email for your domain. When someone sends you a message, their mail server looks up your domain's MX record to find out where to deliver it. Without one, email addressed to your domain cannot be delivered.
What happens if I don't have an MX record?
Email sent to your domain bounces back to the sender as undeliverable. A working website does not mean email works too, since website hosting and email delivery are controlled by separate DNS records. A new domain needs its MX record set up before it can receive mail.
What does MX record priority mean?
Priority is a number that decides which mail server gets tried first when a domain has more than one MX record. Lower numbers are tried first. A common setup uses a primary server at a lower priority number and a backup at a higher one, so mail still arrives if the primary server is briefly unreachable.
How long does it take for an MX record change to take effect?
DNS changes propagate gradually across the internet rather than instantly, typically taking anywhere from a few minutes up to 48 hours depending on the record's TTL setting. That is why the safe approach is to add new MX records before removing old ones, so mail keeps arriving throughout the transition.
Can I check my MX records without technical help?
Yes. A free DNS lookup tool, or the dig MX yourdomain.com command on Mac or Linux, shows a domain's current MX records in seconds. Comparing the result against what your email provider's setup documentation expects usually shows immediately whether something is misconfigured.
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