---
title: "Why do I need an MX record for sending an email?"
date: "2025-02-04T14:30:54+00:00"
summary: "Learn why MX records are crucial for email sending with Amazon SES, ensuring SPF checks and DMARC compliance for your custom domain."
image:
type: "article"
url: "/acquia-cloud-platform/help/61091-why-do-i-need-mx-record-sending-email"
id: "153b2bff-60cb-458a-87b0-8c5e2b838998"
---

Amazon SES requires you to publish an SPF record along with an MX record. An MX record must pass an SPF check while using your custom `MAIL FROM` domain. To define a strict policy that invalidates emails from other sources, Acquia uses a custom `MAIL FROM` domain in the SPF entry. For more information, see [Using a custom MAIL FROM domain](https://docs.aws.amazon.com/ses/latest/dg/mail-from.html). In addition, a custom `MAIL FROM` domain ensures that your emails comply with [Domain-based Message Authentication, Reporting and Conformance (DMARC)](https://docs.aws.amazon.com/ses/latest/dg/send-email-authentication-dmarc.html). DMARC enables a sender’s domain to indicate that the emails sent from the domain are protected by one or more authentication systems.

*   The `MAIL FROM` domain must be a subdomain of the verified identity (email address or domain) that you send an email from. For example, `mail.example.com` is a valid `MAIL FROM` domain for the `example.com` domain. As `mail.<domain>.com` is a common subdomain used by many organizations, Acquia requires that you use `acq-mail.<domain>.com`, which has less chances of conflicting with your existing subdomain.
*   Generally, a subdomain is used for sending an email to isolate the reputation of your emails to the subdomain level only. This does not impact the reputation of your main domain or other subdomains that you use to send emails. For more information about using subdomain for sending emails, see [email subdomains](https://www.mailgun.com/blog/the-basics-of-email-subdomains/).
*   The custom `MAIL FROM` domain (`acq-mail.<domain>.com`) is used as an email envelope address while sending an email to the recipient. Your actual `from` email address, which belongs to the main domain, remains unchanged. At the recipient end, SPF check happens against the envelope address.

The following example shows how SPF check happens when emails are transported with envelope:

![cloud-platform_spf-check-architecture.png](https://acquia.widen.net/content/ee91a999-7407-4748-8945-243edeb18f30/web/cloud-platform_spf-check-architecture.png)