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DNSimple Now Supports Null MX Records

Ivan Bakalov's profile picture Ivan Bakalov on

Today's announcement is a small change that will make a big difference for many of our customers. It's been one of the most requested features, and today we're excited to announce we're adding support for No Service MX (Mail Exchange) resource records, also known as null MX records.

Null MX records allow users to enter only a . in the Exchange field — previously impossible due to validation logic that prevented empty hostnames. This indicates that a particular domain doesn't accept email, which enhances security by reducing attack vectors, like bounce messages or undelivered reports, and improves overall email system efficiency.

These records are now supported on all plans, and are especially useful if you have parked domains that don't have email servers. Let's talk more about how to get set up and how null MX records can enhance your domain security.

How to set up null MX records

A null MX record is created by defining an MX record with a priority of 0 and no associated mail server hostname.

This is the typical format for setting up a null MX record in DNS configuration:

" IN MX 0 ."

  • is the root domain for which the record is being created
  • IN specifies the Internet class.
  • MX indicates that this is a Mail Exchange record.
  • 0 is the priority level, which is set to the lowest possible value to denote that it should never be used to route email.
  • . (dot) signifies that there is no mail server available for the domain.

To set up null MX records for your DNSimple domains:

  1. In the Account header, click the Domains tab, locate the relevant domain, and click the name to access the Domain page.
  2. Navigate to the DNS Record Editor.
  3. In the MX record editor, you can now set Preference: 0 and Exchange: . to indicate your domain's non-receipt of emails.

Creating Null MX Record

What are null MX records?

Null MX records were introduced in RFC 7505 to address the problem of unnecessary email delivery attempts to domains without mail servers. They explicitly indicate that a domain does not accept email, and potentially help improve your domain's reputation and spam scores.

They also save energy. Without null MX records, mail servers can end up retrying to deliver an email for days. This is inefficient and a waste of energy — another aspect of why the null MX record was added apart from its security benefits.

Why you should use null MX records

While null MX records won't change your spam scores directly, they contribute to better email handling and security practices that can enhance your domain's overall reputation.

By declaring that it doesn't accept emails, a domain can avoid unnecessary bounce messages or non-delivery reports, which spammers often exploit. This reduces unwanted email traffic and the potential for the domain to be involved in spamming activities. It also signals that the domain is well-managed, which can help it maintain good standing with email service providers and anti-spam systems.

Get the DNS features you want

We rolled out support for null MX records as a result of your feedback, and we love being able to implement your ideas as part of continually improving DNSimple. Your requests have brought us not just null MX records, but features like WHOIS Privacy Renewal, KEY-Data Support for DNSSEC, and Let's Encrypt Wildcard Support. If there's something you want to see us add, let us know — we always appreciate hearing what features and improvements would make your lives easier.

As always, if you have any questions about null MX records or anything DNS, get in touch and we'll be happy to help.

Not using DNSimple yet? Now's the perfect time to join. Give our robust API and variety of features a try free for 30 days, and let us simplify your dns management.

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Ivan Bakalov's profile picture

Ivan Bakalov

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