What are MX records?

MX records tell the internet which servers receive email for your domain. Learn why they matter for cold email replies and bounces, and how to check them.

Updated October 9, 20262 min read

MX (mail exchanger) records are DNS entries that tell the rest of the internet which servers receive email for your domain. When someone replies to you, their mail server looks up your MX records to find where to deliver the reply.

How MX records work

Each MX record has two parts:

A mail server name, such as mx1.example.com.
A priority number. Lower numbers are tried first. If that server is unavailable, the sender tries the next one.

MX records are about receiving mail. SPF and DKIM are about sending. You need both sides working.

Why MX matters for cold email

Replies. Without working MX records, replies to your campaigns never reach your mailbox, and Distro's Inbox cannot show them.
Bounce notices. Distro learns about bounces from the delivery failure notices that arrive in your mailbox. No MX, no bounce notices.
Trust. A domain that sends email but cannot receive any looks suspicious to spam filters.
Your prospects' MX records. A prospect's domain with no MX records cannot receive email at all, so sending there will bounce.

What it means for Google Workspace users

If your domain's mailboxes are in Google Workspace, your MX records must point to Google. Google sets this up during Workspace sign-up, and its documentation lists the exact MX values to use. Do not copy values from another article or an old setup: Google has changed its recommended records over time.

If you use a free @gmail.com address, Google manages everything and there is nothing to set up.

Example records

These are examples showing the structure, using placeholder server names. Use the values your email provider documents.

Type:  MX
Host:  @
Value: mx1.example-mail-provider.com
Priority: 1

Type:  MX
Host:  @
Value: mx2.example-mail-provider.com
Priority: 5

How to check your MX records

Run nslookup -type=mx example.com (Windows) or dig MX example.com +short (macOS, Linux).
Google's Admin Toolbox includes a free check that reports common MX and DNS problems for a domain.
Send an email to your address from another account and confirm it arrives.

Common mistakes

Leftover records from an old provider. After moving to Google Workspace, delete the old MX records, or some mail may be delivered to the old provider.
Changing MX records by accident when editing DNS for a website. Website changes usually touch A or CNAME records, not MX. Double-check before saving.
Sending from a domain with no mailbox. If you send cold email from a secondary domain, make sure it can receive mail too, or replies and bounces disappear.