Does having an MX record on the from domain improve email deliverability?
Matthew Whittaker
Co-founder & CTO, Suped
Published 24 Apr 2025
Updated 16 Aug 2025
7 min read
When setting up email infrastructure, it's common to focus on sending mail. You have a marketing platform, a transactional email service, or even your own server sending messages. The assumption often is: if the domain is only sending email and not receiving it, an MX (Mail Exchanger) record isn't necessary. After all, MX records are primarily for directing incoming mail, right?
While an MX record's primary function is indeed to route incoming email to the correct mail server, its presence (or absence) on your from domain can significantly impact your email deliverability, even if you never intend to receive replies on that specific address. Let's delve into why this is the case and what it means for your sender reputation and inbox placement.
The role of MX records in email flow
MX records are a fundamental part of the Domain Name System (DNS) for email. They tell other mail servers which server is responsible for accepting emails for a particular domain. Think of it as the postal code for your email address, guiding mail to the right delivery point. Without an MX record, mail servers don't know where to send incoming mail for that domain. As Gcore highlights, MX records are a type of DNS resource record that helps to guarantee that email messages are delivered successfully.
While RFC 5321, the specification for the Simple Mail Transfer Protocol (SMTP), outlines that a mail server should first look for an MX record and then fall back to an A (address) record if no MX record is found, not all mail servers strictly adhere to this fallback behavior in practice. Some may simply check for the presence of an MX record and, if it's missing, treat it as a suspicious signal, even for outgoing mail from that domain.
The rationale here is that a legitimate sending domain should also be capable of receiving email. When a from domain lacks an MX record, it signals to receiving mail servers that the domain might not be fully configured for email, or worse, that it's being used for spam or malicious activity. This can lead to increased scrutiny, delayed delivery, or even outright rejection of your emails. The core idea is that any domain sending email should also be set up to receive email, even if those received emails are simply discarded.
Why MX records matter for outbound email
Receiving servers often perform various checks on the sending domain as part of their anti-spam measures. These checks include looking for a valid MX record. If a sending domain (the domain in the From header) does not have an MX record, it can be seen as an indicator of an illegitimate sender. As Service Objects explains, MX records are essential for email deliverability because they allow email clients and servers to know where to deliver email messages.
The absence of an MX record on the from domain can lead to several problems for deliverability. It makes it harder for receiving servers to verify the authenticity of the sending domain. This can result in your emails being flagged as spam, placed in junk folders, or even rejected outright. This is because it presents a less than complete picture of a trustworthy sender.
Best practice for MX records
Even if your 'from' domain is primarily for sending and you don't expect replies to that specific address, having a valid MX record configured for it is considered best practice. This helps establish the domain's legitimacy and improves trust with receiving mail servers.
If you use a 'no-reply' address, consider directing replies to a different, monitored inbox using a real reply-to email address. This further enhances your sender reputation and gives recipients an avenue for communication.
Impact on sender reputation and blocklists
Domain reputation is a critical factor in email deliverability, and every aspect of your domain's DNS configuration contributes to it. A missing MX record can be perceived as a negative signal, potentially lowering your domain's overall trust score with ISPs and email providers. This can increase the likelihood of your emails landing in the spam folder, or even getting your domain (or IP) placed on an email blocklist (or blacklist).
No MX record on sending domain
Sender reputation: Can be negatively impacted as receiving servers may view it as suspicious or incomplete domain configuration. Lack of a fully configured domain can signal anti-social sending behavior.
Deliverability: Higher risk of emails being flagged as spam, deferred, or rejected. Some mail transfer agents (MTAs) may not perform the A/AAAA record fallback.
Compliance: While RFCs may allow it, practical compliance with ISP expectations often dictates having a receiving email setup.
With MX record on sending domain
Sender reputation: Enhances trustworthiness and signals a legitimate, fully configured email domain. This contributes positively to your sender reputation.
Deliverability: Improves inbox placement rates and reduces the chance of rejection or spam flagging. Receiving servers can easily verify the domain's email infrastructure.
Compliance: Aligns with common industry expectations, even if technical specifications permit omission. It reduces friction with various email security systems.
While MX records are not directly tied to spam or specific blacklists, the absence of expected DNS records can contribute to a lower domain reputation, making your domain more susceptible to being added to an email blocklist (also known as a blacklist). Many blocklists factor in domain configuration and overall legitimacy when making listing decisions.
Practical implications and best practices
Configuring an MX record for your from domain is a straightforward process and generally involves adding a simple record to your domain's DNS settings. This usually points to an existing mail server (even if it's just a placeholder or a server that discards incoming mail for that specific address). An example MX record might look like this:
Example MX recordDNS
yourdomain.com. IN MX 10 mail.yourdomain.com.
If you're using a subdomain for sending, like alerts.yourdomain.com, the MX record would be configured for that subdomain. You can verify your domain's DNS records, including MX, SPF, and DKIM, using an online DNS lookup tool.
Beyond MX records, other DNS records like SPF, DKIM, and DMARC are crucial for email authentication and security. Ensuring all these records are correctly configured signals to receiving servers that you are a legitimate sender and helps prevent your emails from being mistaken for spam or phishing attempts. You can learn more about DMARC, SPF, and DKIM in our comprehensive guide.
Key takeaways for deliverability
Having an MX record on your sending domain (the from address) is not explicitly required by core RFCs if you only send mail, but it is highly recommended for improving deliverability. Modern email systems and spam filters often perform comprehensive checks, and a missing MX record can be a red flag. It's a simple step that greatly contributes to your domain's credibility and email acceptance rates.
Ensuring your entire email infrastructure is properly configured, including MX records, SPF, DKIM, and DMARC, creates a robust and trustworthy sending profile. This proactive approach minimizes the chances of your emails being caught in spam filters and maximizes their chances of reaching the inbox. Remember, a fully configured domain is a sign of a responsible sender.
Regularly monitoring your email deliverability and ensuring your DNS records are correct will help you maintain a healthy sender reputation. You can also monitor for blocklist (or blacklist) listings, which can be an indicator of underlying deliverability issues.
Views from the trenches
Best practices
Always publish an MX record for your sending domains, even if they only send mail. This validates your domain.
Configure a simple MX record that points to a server designed to accept, or even just discard, incoming mail.
Use a real, monitored email address for your Reply-To header to enhance recipient engagement.
Common pitfalls
Assuming that if a domain only sends mail, it doesn't need an MX record, leading to deliverability issues.
Ignoring mail server responses or warnings related to missing DNS records.
Using 'no-reply' email addresses without a proper return path or reply-to strategy.
Expert tips
Some spam filters and scanning tools prioritize MX record existence over A/AAAA records for legitimacy checks.
Sending from a domain that cannot receive mail can be seen as an 'anti-social' behavior by ISPs.
Even minimal MX record configuration is less intrusive for receiving servers than trying to ping port 25.
Expert view
Expert from Email Geeks says that both the 5321 (Mail From) and 5322 (From) domains should be configured to accept mail for optimal deliverability.
April 4, 2023 - Email Geeks
Expert view
Expert from Email Geeks says that sending mail from a domain that does not accept mail is considered bad practice within the email community.
