What Is an MX Record? How Email Routing Works

An MX record is the DNS entry that tells sending mail servers where to deliver email for your domain. If you want messages sent to your custom address to arrive properly, your domain needs a valid MX record, and if you use more than one mail server, the lowest priority number is tried first.

Many small business owners run into this when they set up an address like you@yourbusiness.ca and then wonder why mail still isn't arriving. Your website can work fine while your email stays broken, because web traffic and mail delivery use different DNS records. We see this confusion all the time, and it matters because email reliability starts with the right routing record.

If you prefer a simple analogy, think of your domain as a business name on an envelope. The MX record is the sorting instruction that tells the internet which mail room should receive that envelope. Without that instruction, incoming mail has nowhere valid to go.

Your Custom Domain and the Role of MX Records

Say you've just bought a domain for your business and want a proper address instead of a free mailbox. That's a normal next step. A custom domain looks more professional, matches your brand, and gives you control over where your email lives.

But buying the domain isn't enough. When someone sends a message to your new address, their mail server has to ask, “Which system handles email for this domain?” The answer comes from the MX record.

A common situation goes like this. Your website launches, your business cards are printed, and test emails vanish because the domain has no mail routing yet. As our custom email domain setup guide explains, email on a custom domain depends on DNS records that point traffic to the right service.

Without valid MX records, a domain can't receive email at all.

That's why MX records aren't an optional technical extra. They're one of the basic pieces that make your custom email address work in practice.

What Is an MX Record Exactly

An MX record stands for Mail Exchanger record. It lives inside the Domain Name System, or DNS, which works like the internet's directory for domain names. DNS helps systems find the right destination, and the MX record is the part of that directory used for email.

If you've searched for “what is MX record” or “MX record meaning,” the shortest accurate answer is this. It tells sending mail servers where to deliver email for your domain. Proofpoint explains that MX records can include multiple mail servers with priority values, and the server with the lowest number is tried first. That design supports failover and load balancing in email routing, which is why correct MX setup is a core reliability control for delivery (Proofpoint on MX records).

The three parts that matter most

When you look up an email MX record, you'll usually see three practical pieces of information:

The hostname needs to be a proper mail server name, not just any value in DNS. The priority tells the sender which destination to try first. The TTL affects how fast updates become visible after a change.

Why this matters to a small business

For a business owner, the technical details only matter because of the outcome. If your MX record points to the right mail host, customers can reach you. If it points to the wrong place, messages may bounce, disappear, or land at a provider you no longer use.

Practical rule: Your website domain and your email routing are related, but they are not the same setting.

That's where many people get tripped up. They update a website record and assume email will follow. It won't. Email needs its own routing instructions.

How MX Records Route Your Email

A message doesn't travel straight from one inbox to another. It moves between mail servers. The moment that matters most is when the sender's server checks your domain to find the right receiving server.

Here's the flow in plain language.

The path a message follows

1. Someone sends an email to your domain.
2. The sender's mail server checks DNS for your domain's MX record.
3. DNS returns the listed mail server hostnames and their priority values.
4. The sender connects using SMTP, which stands for Simple Mail Transfer Protocol.
5. Your receiving mail server accepts the message and places it in the mailbox.

That DNS lookup is the key step. The sender doesn't guess where your mailbox lives. It asks DNS for the routing instructions.

A technical review from EmailLabs describes the MX record as the foundational signpost for the SMTP handshake. When email is sent to a recipient domain, the sender's mail transfer agent queries DNS for the MX record. The same review notes that if an MX record points directly to an IP address instead of a fully qualified domain name, remote mail servers reject it as an invalid MX format, resulting in a 0% delivery success rate for that domain (EmailLabs on MX record routing).

Here's a short visual explainer if you want to see that journey in another format.

Where readers usually get confused

People often assume the mail server is the same as the website host. Sometimes it is, but often it isn't. A domain can use one provider for the site and another for email.

Another common misunderstanding is the idea that email goes to an inbox first and then gets sorted. In reality, the sender has to find the right receiving server before the message can even be delivered.

If the sender can't find a valid mail destination for your domain, the conversation ends before your inbox ever comes into play.

That's why a working MX record is part of basic deliverability, not an advanced extra.

Understanding MX Record Priority Values

The MX priority value tells sending servers which listed mail server to try first. Lower numbers have higher preference. So if one server has priority 10 and another has priority 20, the sender tries 10 first.

This setup is useful for reliability. If the first server is unavailable, the sender can try the next one. That's the practical value of having more than one MX entry.

Two common priority patterns

If two servers share the same priority, SMTP rules require the sender to balance traffic instead of always picking one. That helps prevent all mail from piling onto a single destination.

For a small business, this usually comes down to one question. Do you want one receiving server or a primary and backup? If continuity matters, priority values give you a way to build that into your domain's mail routing.

How to Find and Check Your MX Records

An MX record lookup is one of the fastest checks you can do when email isn't arriving. You don't need to be a DNS specialist to confirm whether your domain is publishing the right mail routing.

Easy ways to check

You can use a browser-based lookup tool such as MXToolbox to see what the public internet currently sees for your domain. That's often the easiest option for a business owner or office admin.

If you manage your own DNS, your provider's dashboard may also show your current records. If you host mail with a service that supports custom domains, its setup page should list the exact hostname and priority you're expected to publish. For example, Typewire's domain help documentation shows where custom domain mail settings fit into setup.

What to look for in the result

When you check your records, compare the result against the settings from your mail provider.

• Correct hostname. Make sure the MX entry points to the mail server name your provider gave you.
• Expected priority. Confirm the numbers match the intended order.
• Single active provider. Old entries from a previous service can create confusion.
• Reasonable TTL. During changes, a shorter cache window can help updates spread faster.

A lot of MX problems aren't deep technical failures. They're simple mismatches between what you meant to publish and what DNS is showing.

Check from the outside, not just inside your DNS panel. Public lookup results show what other mail servers can really see.

Common MX Record Mistakes and How to Fix Them

Most MX trouble comes from a short list of mistakes. The good news is that they're usually fixable once you know what to inspect.

Pointing the MX record to the wrong kind of target

The biggest error is using the wrong destination format. MX records should point to hostnames, not raw addresses. MXToolbox notes that MX records are the gatekeeper for domain-based email because without valid MX records a domain cannot receive email at all, and it also notes common TTL values such as 3,600 seconds for faster propagation during migration and 86,400 seconds for stability (MXToolbox on what an MX record is).

If your provider gives you a mail host, enter that host exactly as provided. Don't replace it with something that looks simpler. The mail system expects a proper server name.

Leaving old provider records in place

This happens often during migrations. You switch to a new mail host, but the previous provider's MX records remain in DNS. Sending servers may then see a mixed set of destinations, which can send mail to the wrong place.

A simple clean-up rule helps here:

• Keep only current MX entries. Remove records from providers you no longer use.
• Review related DNS changes together. Mail migrations often involve more than one record type, so document the change before you publish it.

If you're planning a move, a shorter TTL can help the change spread more quickly. Once everything is stable, many teams move back to a longer TTL for consistency.

Typos and bad assumptions

Small spelling mistakes in the mail hostname can break routing completely. So can assumptions like “my web host must also handle email” or “the old records probably don't matter.”

A quick audit usually catches these issues:

If you're also working on inbox placement and sender reputation, our email deliverability guide covers the next layer beyond DNS setup.

The practical takeaway is simple. Treat your MX record like critical business infrastructure. Check it when you launch a domain, check it after any migration, and check it whenever mail starts acting strangely.

Last updated: 18 June 2026

If you want private email on your own domain under Canadian jurisdiction, Typewire is one option to consider. We run our own infrastructure in Canada, support custom domains, and give you direct control over the DNS settings that make inbound email work reliably.