When someone sends an email to your business address, their mail server needs to know where to deliver it. It does not guess, and it does not look up your website's IP address. Instead, it queries a specific type of DNS record - the MX record - which points to the mail server responsible for accepting email on behalf of your domain.
Understanding MX records matters any time you set up a new domain, switch email providers, or troubleshoot a delivery problem. Here is everything you need to know.
What MX Records Do
MX stands for Mail Exchanger. An MX record is a DNS entry that maps your domain name to one or more mail servers. When a sending mail server wants to deliver a message to hello@yourbusiness.ca, it performs a DNS lookup specifically for MX records associated with yourbusiness.ca. Whatever hostname those MX records point to is where the email gets delivered.
The key distinction: MX records point to a hostname (like mail.yourbusiness.ca or aspmx.l.google.com), not directly to an IP address. That hostname then has its own A record that resolves to an IP. This indirection allows mail infrastructure to change IP addresses without requiring MX record updates.
Understanding MX Priority Values
Every MX record has a priority number (sometimes called preference). When there are multiple MX records for a domain - which is common - the sending server tries the one with the lowest number first. Lower number means higher priority.
For example:
10 mail1.yourbusiness.ca- primary mail server, tried first20 mail2.yourbusiness.ca- backup mail server, used if the primary is unreachable
This is how backup or failover mail servers work. If your primary mail server is unavailable, sending servers will automatically queue and retry using the lower-priority (higher-numbered) backup. Some businesses use a secondary MX record pointing to a service that holds mail during outages and delivers it once the primary comes back online.
How to Check Your MX Records
The fastest way to check your current MX records is MXToolbox at mxtoolbox.com. Type your domain name into the MX Lookup tool and it will show you all MX records currently published in DNS, including their priority values and the IP addresses the hostnames resolve to.
You can also check MX records from a Mac or Linux terminal:
dig MX yourdomain.ca
Or from Windows Command Prompt:
nslookup -type=MX yourdomain.ca
This is useful for quickly verifying that a change has propagated or confirming what your domain is currently using.
Changing MX Records When Switching Email Providers
If you are moving from your hosting company's built-in email to Google Workspace, Microsoft 365, or Zoho Mail, the switch requires updating your MX records. Each provider gives you specific MX record values during their setup process.
For Google Workspace, you will add five MX records pointing to Google's servers (aspmx.l.google.com and variations) with specific priority values that Google provides.
For Microsoft 365, you will add a single MX record pointing to a Microsoft-generated hostname like yourdomain-ca.mail.protection.outlook.com.
For Zoho Mail, you will add two MX records pointing to Zoho's servers.
The process for updating MX records depends on where your DNS is managed - usually either your domain registrar or your hosting provider. In cPanel, MX records are managed under Email > MX Entry. At most registrars, you can find DNS management in the domain settings area.
Important: Before changing MX records, make sure you have completed the email provider's full setup (including verification and account creation). Changing MX records before the receiving side is ready will cause incoming email to be lost or rejected.
Propagation Delay
DNS changes, including MX record updates, do not take effect instantly worldwide. Propagation - the time it takes for DNS servers around the world to pick up the new information - typically takes between 15 minutes and 48 hours, depending on the TTL (time-to-live) value of your existing records and your DNS provider's infrastructure.
Most modern DNS providers propagate changes within an hour. If you have set a low TTL (300 seconds or lower) in advance of a planned migration, you can usually see the change taking effect within minutes.
During propagation, some senders may reach your old mail server while others reach the new one. This is normal and temporary. Most businesses plan email migrations during low-traffic periods - evenings or weekends - to minimize any disruption.
Understanding how MX records work takes the mystery out of email delivery and gives you confidence when making DNS changes that matter.
