What is MX Record in DNS?

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The MX record is the DNS record type responsible for controlling sending and receiving emails. Without an MX record, the user can not send and receive mail from the other end user. If you are confused about how it works, you can check your domain’s “mail exchange” record by doing a quick MX lookup online. This is a vital domain name system record as it is responsible for routing and delivering emails to the correct address.

Unfortunately, many Internet users don’t know the meaning and usage of MX records. This article will discuss some topics related to the MX record and the MX lookup tool. This article will cover the basics of the following:

  • What is the DNS MX Record and its Purpose?
  • What are the MX Record Levels?
  • How to Check an MX Record?

If you’re in the networking field or interested in learning about it, read it thoroughly.

What is the MX Record and its Purpose?

In the Domain Name System (DNS), an MX record is a resource record. The system provides, among other things, information regarding which IP addresses must receive emails.

Moreover, an MX record contains a hostname and priority code for the computer(s) handling emails for a domain. The host’s IP address is indicated in the A-record of the host, which routes email to the IP address.

The primary function of an MX record is to instruct servers on where to send emails. And the Simple Mail Transfer Protocol (SMTP) is used for this purpose. This record type provides nameservers with information about the location of the domain “mailbox.” For this record type to function correctly, it must point to an A or AAAA record.

Domain names are associated with IP addresses through the A record (or address-record). In this record, the domain name is translated into an IP address.

Example of an A-record:

  • Domain: google.com
  • Hostname: mail
  • IP-address: 11.22.33.222

There is now a mail server called mail.google.com, which can be used in the MX records.

Example of an MX record:

  • Domain: google.com
  • Mail exchanger: mail.google.com
  • Priority: 10

Additionally, similar to CNAME records, MX records must always point to a domain, hostname, or address record (rather than an IP address). The following is an example of an MX format. 

myserver.comRecord type:priority:value:TTL
@MX10mailhost1.myserver.com45000
@MX20mailhost2.myserver.com45000

According to the priority number, the lowest priority number record is the most preferred. Using the above MX record, the nameservers attempt to reach the domain name with the lowest priority, 10. 

However, if the server cannot resolve that domain, it falls back on the second domain. Using the same priority number, you can configure both MX records to receive the same amount of emails.

What are the MX Record Levels?

In MX records, you can set the level of mail servers in your configuration. And the levels determine which mail server to use first. A lower priority level indicates a higher priority. To avoid disruptions in your domain’s email services, it is recommended that you have multiple MX records. 

Although MX records do not support failover, prioritizing mail servers by level achieves the same result. It is possible to have several MX records at the same level, just as you would with a round-robin configuration. 

By setting up the email servers in this manner, the servers will balance the load between them equally and randomly.

How to Check an MX Record?

Checking your MX record can be done online or locally on your device. While checking MX records may be beneficial, there are also some downsides. 

By Using Online MX Tool

Using an online MX lookup tool is the most convenient way to verify your DNS MX record. 

You just need to search the MX lookup tool on the Internet and go there. Once you access the MX tool, you just need to enter the domain name you want to check the MX records. It will automatically show the results within a matter of seconds.

Using Chrome Extension

You can quickly check the MX record of your website using the Google Chrome DNS lookup extension. Many online SaaS platforms feature online MX lookup tools, which are also available as Chrome extensions. 

You just need to choose the one that offers the highest functionality and works free of cost. 

By Using Nslookup Command on Windows

Using the nslookup command on your Windows operating system, you can find MX records. Additionally, the command allows you to specify the DNS server you want to use. The following instructions will illustrate how to use nslookup on your Windows device.

nslookup > set q=mx > myserver.com

For instance, if you would like to use a specific DNS resolver, the command would be as follows:

nslookup > set q=mx > server 10.121.191.1 > myserver.com

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