MX (Mail Exchange Record)

The MX (Mail Exchange) Record is a type of DNS record in the Domain Name System (DNS) that specifies a mail server responsible for receiving email messages on behalf of a recipient’s domain. An MX record is used to tell which mail servers accept incoming mail for your domain and where emails sent to your domain should be routed to.

Components of MX Record:

  1. Preference Value: This is a priority number that indicates which mail server should be used first. Lower values are prioritized over higher values. If two mail servers have the same priority, the sender’s server will attempt to send mail to them in no particular order.
  2. Mail Server Hostname: This is the domain name of the mail server. It must have a corresponding A (Address) or AAAA (IPv6 Address) record in the DNS zone.

Example of MX Record:

For the domain “example.com”, an MX record might look like this:

Priority: 10
Mail Server: mail1.example.com

And another with:

Priority: 20
Mail Server: mail2.example.com

In this case, sending mail servers will try to deliver email to mail1.example.com first. If that server doesn’t respond, they will attempt to deliver to mail2.example.com.

Importance of MX Records:

  1. Email Routing: Without MX records, the internet wouldn’t know where to deliver emails sent to a particular domain.
  2. Backup Servers: By providing multiple MX records with different priorities, a domain can specify backup mail servers. This is useful if the primary mail server fails.
  3. Load Distribution: For larger organizations, multiple MX records might be used to distribute the load of incoming email across several servers.
  4. Filtering and Security: Some organizations use MX records to specify mail servers that perform initial filtering for spam or malware before delivering the email to the primary mail server.

When querying a domain’s DNS for its MX record, you will get information about which mail server or servers the domain uses. This is essential for mail delivery on the internet. If a domain doesn’t have an MX record set up, it won’t be able to receive emails.

Key terms in plain language

Open a term for a concise explanation of language used on this page.

Fiber Internet

Internet delivered through strands of glass using light. Fiber commonly supports high capacity, low latency, and strong upload performance, but availability must be confirmed for the exact address.

Cloud Computing

Computing resources—such as applications, servers, storage, or databases—delivered from remote infrastructure and scaled as requirements change.

Infrastructure as a Service (IaaS)

Cloud-based servers, storage, and networking that customers configure and manage without owning the underlying data-center hardware.

Software as a Service (SaaS)

Software accessed as an online service instead of being installed and maintained entirely on the customer’s own computers or servers.

Disaster Recovery (DRaaS)

A plan and service for restoring applications, data, and operations after an outage or disruption. DRaaS provides recovery infrastructure through a managed cloud service.

Identity and Access Management (IAM)

The systems and policies that determine who a user is, what resources they may access, and how that access is authenticated and reviewed.