What are MX Records?

When you start using ImprovMX, you'll be asked to add our MX Records on your DNS control panel. So, what are these and why are they needed?

Put simply, MX records are a type of DNS record that allow mail services to determine where email for a particular domain should be routed.

Each domain that should receive email requires MX records so the sending email service knows where to direct the message.

Without MX records, no email can be received at that domain!

Example

Let's look at a quick example to illustrate this.

Here is the (fictitious) email address of our Chief Happiness Officer, Richard Hendricks:

richard.hendricks@improvmx.com

As you will know, an email address is composed of two parts, divided by the @ sign.

In the example above, the part before the @ sign is known as the alias.

The part after the @ sign is the domain.

When sending an email from your email system to this address, the first thing that will happen is the server looks up the DNS MX records for the target domain, which in this case is improvmx.com. You can also look this up yourself using services such as check.mx and mxtoolbox.com.

A lookup will reveal that the MX records for improvmx.com are as follows:

This tells the sending email service that the email should be routed to the above addresses. Only when the email reaches the destination email server will the alias (before the @ sign) be used to determine what should happen to the email internally.

Preference / Priority

But wait - what does the preference (also known as priority) refer to?

This simply offers a level of redundancy by allowing multiple MX records to be added. In the event of a failure or outage, a different destination server can be utilised instead.

Email servers should use MX records with the lowest number priority first, and will fall back to others if unavailable. So, in this case, the MX record with priority 10 will be used first - mx1.improvmx.com . In the event that no response is received from that server, the lower priority server will be tried instead (mx2.improvmx.com).

The actual numbers don't matter, only the relative order. So priority 1 & 2 would have the same effect as priority 10 & 20 in the above scenario.

That's it!

You have now a basic understanding of how MX records are used to direct email, both on your incoming messages and on mails you send to others.