Definition
MX (Mail Exchange) records tell the internet which mail servers are responsible for accepting email addressed to your domain. Every domain that sends or receives email must have at least one MX record. Without one, you cannot receive bounces, replies, or FBL reports.
Record Format
yourdomain.com. IN MX 10 mail.yourdomain.com.
yourdomain.com. IN MX 20 backup.yourdomain.com.
- Priority number: Lower numbers are tried first (10 is higher priority than 20)
- Mail server: The hostname of your mail server
- Multiple records: Backup servers provide redundancy if the primary fails
Common Mistakes
Using CNAME records for MX targets (most standards prohibit this), setting all MX records to the same priority, and forgetting to update MX records after changing ESPs.
Why It Matters
This matters because the choices you make here show up directly in your results. Without one, you cannot receive bounces, replies, or FBL reports. When this is handled well it supports engagement, delivery, and the trust subscribers place in your brand; when it is neglected, the effects tend to show up in declining performance and harder-to-fix problems further down the line.
Best Practices
- Have at least two MX records for redundancy
- Set the priority gap wide enough (10, 20, 30) that failover works predictably
- Ensure MX record hostnames have corresponding A records
- Monitor MX record availability as part of your deliverability infrastructure
Was this useful?
Related Glossary Terms
Abuse Complaint
An abuse complaint is a report from a recipient who marks an email as spam, which negatively affects sender reputation and deliverability.
Alt Text
Alt text is the written alternative to an image in an email, displayed when images are blocked, slow to load, or consumed by screen readers.
AOL Mail for Email Marketers
AOL Mail is a legacy email provider with specific deliverability requirements and rendering quirks, now operating as part of the Yahoo+AOL network under shared infrastructure.
Email Authentication Protocols
Email authentication protocols are technical standards that verify the identity of an email sender, helping mailbox providers distinguish legitimate mail from spam and phishing.
BIMI
BIMI (Brand Indicators for Message Identification) is an email standard that allows brands to display their logo next to their emails in supported email clients. It requires DMARC enforcement at quarantine or reject policy.
Bounce Management
Bounce management is the process of handling emails that are rejected by mailbox providers, including classification, removal of bad addresses and protection of sender reputation.
Frequently Asked Questions
Good practice here means handling Email MX Record Setup in a way that is relevant, timely, and honest for your audience. MX record setup configures the mail exchange records that specify which servers accept incoming email for your domain, which is essential for receiving replies, bounces, and feedback loop reports. Done well, it improves engagement and builds trust; done poorly, it creates friction that costs you results.
Because it touches the parts of email that drive outcomes: relevance, trust, and delivery. Small improvements compound, while repeated mistakes quietly erode the health of your programme.
The most common problems are treating Email MX Record Setup as a one-off task, ignoring what the data says, and copying competitors without testing. All three lead to effort that does not translate into better results.
Compare the metrics it should influence — engagement, conversions, and deliverability — before and after you make changes. Trends over time matter far more than any single send.
It supports the same goal as the rest of your email programme: the right message to the right person at the right time. Aligned with segmentation and automation, it reinforces everything else rather than competing with it.