---
title: "What Is an MX Record? Mail Exchanger Record Definition | ONEGTMLAB"
description: "An MX record is the DNS entry that tells sending servers where to deliver email for a domain. Learn how MX records work and why they matter for cold email."
canonical: https://www.onegtmlab.dev/glossary/mx-record
---

# What Is an MX Record? Mail Exchanger Record Definition | ONEGTMLAB

[![](/_astro/69a56255e2154ea94c75641b_onegtm-nav-logo.CkLAn8xX.svg)](/)

[

Book a call

](/book)

GTM Glossary

# MX Record

An MX record (mail exchanger record) is a DNS entry that names the mail server responsible for accepting email for a domain, along with a preference number that sets its priority.

Also called: MX, mail exchanger record, mail exchange record

## Why it matters

Every email sent to an address at a domain depends on that domain's MX records. A sending server looks them up, tries the host with the lowest preference number first and falls back to the others if it cannot connect. When MX records are missing or point to a host that does not accept mail, messages to that domain can bounce or never arrive.

In outbound, MX records do two jobs. Your own sending domains need working MX records so replies and bounce notices arrive. When you clean a prospect list, an MX lookup shows whether a domain accepts mail at all and which provider hosts it. MX records control where a domain receives mail, while SPF, DKIM and DMARC deal with authenticating the mail a domain sends.

## Example

A company sets up the sending domain acme-mail.example for outbound. It adds two MX records: mx1.mailhost.example with preference 10 and mx2.mailhost.example with preference 20. Servers delivering replies try mx1 first and use mx2 only if mx1 is unreachable. Before each campaign, the team also looks up the MX records of prospect domains and removes any domain that returns none.

## Related terms

-   [SPF Record](/glossary/spf-record)
-   [DKIM](/glossary/dkim)
-   [DMARC](/glossary/dmarc)
-   [Email Deliverability](/glossary/email-deliverability)
-   [Email Verification](/glossary/email-verification)

## Related service

[GTM Engineering Signal-led outbound systems that enrich, score, sequence and sync to your CRM.](/ai-gtm-engineering)

## Related playbook

-   [Cold Email Playbook Domains, a verified list, a mail gateway gate, final-text copy and launch checks, in that order.](/growth-playbooks/cold-email)

[← All GTM terms, A to Z](/glossary)

GET STARTED

## Turn the definition into a working system.

We build the GTM Engineering systems behind terms like this one. Tell us where your pipeline breaks and we will show you what we would fix first.

[

Book a Strategy Call

](/book)[

See Case Studies

](/case-studies)

[![](/_astro/69a56255e2154ea94c75641b_onegtm-nav-logo.CkLAn8xX.svg)](/)

COMPANY

[

Why Us

](/#why-us)[

Process

](/#timeline)[

Blogs

](/blogs)[

About

](/about)[

Clients

](/clients)[

Free resources

](/free-resources)[

Newsletter

](/newsletter)

Services

[

GTM Engineering

](/ai-gtm-engineering)[

Account-Based Marketing

](/services/account-based-marketing)[

Paid Media

](/services/paid-media)[

Content Engineering

](/linkedin-personal-branding)[

RevOps

](/services/revops)[

SEO, AEO & GEO

](/services/seo-aeo-geo)[

All services

](/services)

© 2026 ONEGTMLAB Private Limited. All rights reserved.

![](/_astro/wordmark-3d.m-LgRZCQ.svg)