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DNS A Record vs MX Record: What’s The Difference?

WRITTEN BY
Timothy Shim
UPDATED
April 23, 2024

 

The Domain Name System (DNS) is a hierarchical naming system that can map domain names to IP addresses and other information. DNS is essential to the operation of the internet, and it allows users to access websites, send and receive email, and use other online services.

 

Two common types of DNS records are A and MX, which serve different purposes. In this article, we will explore the differences between DNS A records and MX records.

 

 

What is a DNS A Record?

 

DNS zone editor in cpanel

Most control panels make DNS Zone handling easy. (Credit: cPanel)

 

A DNS A record maps a domain name to an IP address. When a user types a domain name into their web browser, the DNS resolver queries the DNS server for the IP address associated with the domain name.

 

The DNS server responds with the IP address, and the web browser uses it to connect to the web server and display the website.

 

The format of a DNS A record is as follows:

 

IN A

 

For example, if you wanted to map the domain name “example.com” to the IP address “192.0.2.1,” you would create the following A record:

 

example.com. IN A 192.0.2.1

 

The “IN” stands for “Internet” and indicates the class of the record. The “A” indicates the type of record, an IPv4 address. The IPv4 address is specified as four decimal numbers separated by periods, such as “192.0.2.1.”

 

 

What is a DNS MX Record?

 

MX record pointing to A record

Interestingly, MX records can point to A records. (Credit: DNS Made Easy)

 

A DNS MX record is used to specify the mail server responsible for handling email messages for a domain name. When a user sends an email to an address at a domain name, the sender’s mail server queries the DNS server for the MX record associated with the domain name.

 

The DNS server responds with the mail server’s hostname, and the sender’s mail server uses it to deliver the email.

 

The format of a DNS MX record is as follows:

 

IN MX

 

For example, if you wanted to specify that the mail server responsible for handling email messages for “example.com” is “mail.example.com,” you would create the following MX record:

 

example.com. IN MX 10 mail.example.com.

 

The “10” indicates the priority of the mail server. If multiple MX records are specified for a domain name, the mail server with the lowest priority number is tried first. If that server is unavailable, the next server with the following highest priority number is tried, and so on.

 

 

Differences Between DNS A Records and MX Records

 

DNS record in Cloudflare

Example of DNS Records in Cloudflare. (Credit: Tech Otaku)

 

While DNS A records and MX records both serve essential functions in the DNS system, there are several key differences between them.

 

  • Mapping domain names to IP addresses vs. specifying mail servers
    The most significant difference between DNS A records and MX records is their purpose. A DNS A record maps a domain name to an IP address, while an MX record specifies the mail server responsible for handling email messages for a domain name.
  • Type of data stored
    A DNS A record stores an IPv4 address, a 32-bit numerical address used to identify devices on a network. On the other hand, a DNS MX record stores information about the mail server responsible for handling email messages for a domain name. An MX record does not store an IP address but rather a hostname corresponding to the mail server.
  • Format
    The format of an A record is relatively simple and consists of three parts: the domain name, the class, and the IPv4 address. The IPv4 address is the numerical address of the server that the domain name should point to.
     
    On the other hand, an MX record specifies the mail server responsible for handling email messages for a domain name. The format of an MX record is slightly more complex than an A record. It consists of the domain name, the class, and the mail server name.
  • Priority
    Priority is not typically used with A records since it doesn’t prioritize between multiple servers or hosts. When a DNS resolver queries for an A record, it receives a single IPv4 address in response. The DNS resolver then uses this IP address to connect to the appropriate server or host.
     
    On the other hand, MX records use priority to indicate the order in which mail servers should be contacted. An MX record specifies the mail server responsible for handling email messages for a domain name. If a domain has multiple mail servers, priority indicates the order in which they should be contacted.
  • Usage Frequency
    A records are frequently used to set up web servers, mail servers, and other services that rely on domain name resolution. A DNS resolver queries the DNS servers for the corresponding A record whenever a user types a domain name into a web browser. Therefore, A records are used frequently.
     
    MX records, on the other hand, are used specifically for email routing. They are used to specify the mail server that is responsible for handling email messages for a particular domain name. MX records are used less frequently than A records, as email is not typically sent as frequently as web requests. However, they are still essential for email delivery, and any issues with MX records can lead to problems with email delivery.

 

 

Handling A Records and MX Records in Web Hosting Control Panels

 

Many reputable web hosts offer control panels that allow easy management of hosting settings. That includes DNS records such as A and MX records. However, how these control panels handle A and MX records can differ depending on the hosting provider and control panel software used.

 

Hostinger hpanel

Hostinger’s hPanel dashboard.

 

A records are typically managed through a section of the control panel dedicated to DNS management. Users can view, edit, and add A records for their domain names in this section. The user can typically enter the hostname (such as “www” or “mail”), the IP address of the server where the website or service is hosted, and the time-to-live (TTL) value.

 

Some control panels may offer advanced settings such as wildcard A records or reverse DNS.

 

MX records are also managed through the DNS management section of the control panel but may be located in a separate sub-section specifically for email routing. The user can view, edit, and add MX records for their domain name in this section.

 

The user can enter the mail server’s hostname, the priority value, and the server’s IP address where the mail server is hosted. Some control panels may offer advanced settings such as mail exchanger weighting or backup MX servers.

 

Some web hosting control panels may offer additional features or integrations for managing A and MX records, such as automated DNS management, DNS templates, or third-party DNS services.

 

 

DNS Records Serve Mostly Unique Functions

 

Understanding the differences between DNS A and MX records is essential for adequately configuring domain name resolution and email routing.

 

While A records map domain names to IP addresses for web servers and other services, MX records specify the mail server responsible for handling email messages for a domain name. Both records are essential for proper website function in delivering web and email services to users.

 

By understanding the data stored, format, priority, and usage frequency differences between A and MX records, website owners can correctly configure their DNS settings for optimal performance and reliability.