SOLVED: Reverse DNS Does Not Match SMTP Banner in cPanel (2024)

In your email communication, ensuring proper email delivery is of utmost importance for businesses and individuals alike.

One crucial factor that affects email deliverability is the alignment between the Reverse DNS and the SMTP banner in cPanel. The SMTP banner, a greeting message sent by the mail server during an SMTP connection, is vital in identifying and verifying the sending server.

When the Reverse DNS does not match the SMTP banner in cPanel, it can lead to email delivery problems, potentially causing emails to be rejected or marked as spam.

In this blog post, we will explore the significance of the SMTP banner in cPanel, the consequences of a mismatch between Reverse DNS and SMTP banner, and the steps to troubleshoot and resolve this issue for seamless email delivery.

What is the SMTP Banner in cPanel?

The SMTP banner in cPanel is a configuration setting that determines the greeting message sent by the mail server when establishing an SMTP connection. It serves as the initial message that the receiving server sees when a connection is made, containing essential information about the server, such as its hostname and software version.

The SMTP banner is critical in email communication as it helps other mail servers identify and verify the sending server.

The SMTP banner ensures a secure and reliable email exchange between servers by establishing trust and preventing spam and abuse.

A properly configured SMTP banner is crucial for maintaining a positive reputation and credibility for your domain’s emails.

Consequences of Reverse DNS and SMTP Banner Mismatch in cPanel

When the Reverse DNS does not match the SMTP banner in cPanel, it can significantly affect email delivery.

The mismatch can trigger suspicions or indicate a misconfiguration to other mail servers, leading to various email delivery issues. Some of the consequences include:

Email Rejection and Spam Marking: Emails sent from a server with a mismatched Reverse DNS and SMTP banner may be rejected or flagged as spam by other mail servers. This can result in critical emails not reaching their intended recipients.
Delayed or Failed Email Delivery: Mismatched Reverse DNS and SMTP banner can cause delays in email delivery or result in failed deliveries, leading to frustration for both the sender and the receiver.
Reputation Damage: Consistently having email delivery issues can harm the reputation and credibility of the sending domain. It may lead to recipients viewing emails from the domain with suspicion or distrust.
Loss of Business Opportunities: Failed email delivery can result in missed business opportunities, potential leads, or customer communication, negatively impacting business growth.
Difficulty in Communication: When emails fail to reach their destination due to the mismatched Reverse DNS and SMTP banner, it can hinder effective communication with clients, customers, or business partners.

How to Fix Reverse DNS and SMTP Banner Mismatch in cPanel

To resolve the issue of Reverse DNS and SMTP banner mismatch in cPanel, several steps can be taken based on the specific situation. Here are some solutions to consider:

1. Change SMTP Banner Option to Match Reverse DNS Value:

Log in to your cPanel WHM (Web Host Manager) panel.
Navigate to the Exim Configuration Manager.
Look for the “smtp_banner” option and ensure it is correctly configured with the desired greeting message or reverse DNS value.
Update the SMTP banner to match the Reverse DNS value by adding the following code:

smtp_banner = $myhostname ESMTP $tod_full

Save the changes.

2. Update Reverse DNS to Match SMTP Banner:

Ensure that the Reverse DNS (PTR) record for the server’s IP address matches the hostname configured in cPanel.
If the Reverse DNS does not match the SMTP banner, consider updating the PTR record to match the hostname.

If changing the SMTP banner option or updating the Reverse DNS does not resolve the issue, it may be necessary to seek assistance from the hosting provider or system administrator.

They can provide further guidance and support in troubleshooting and resolving the issue.

How to Troubleshoot SMTP Banner Issues in cPanel

To troubleshoot SMTP banner issues in cPanel, follow these steps:

1. Check the SMTP Banner Configuration:

Log in to your cPanel WHM panel.
Navigate to the Exim Configuration Manager.
Look for the “smtp_banner” option and verify if it is correctly configured with the desired greeting message or reverse DNS value.

2. Verify Reverse DNS Configuration:

Ensure that the Reverse DNS (PTR) record for the server’s IP address matches the hostname configured in cPanel.
If the Reverse DNS does not match the SMTP banner, consider updating the PTR record to match the hostname.

3. Allow Time for DNS Propagation:

After making any changes to the SMTP banner or Reverse DNS, allow time for DNS propagation to occur. It may take some time for the changes to propagate across the internet.

4. Test Email Delivery:

Send a test email to check if the SMTP banner issue has been resolved.
Monitor the email delivery and check for any bounce-back messages or delivery errors.

If the above steps do not resolve the SMTP banner issues, it is advisable to seek assistance from your hosting provider or system administrator.

They can provide further guidance and support in troubleshooting and resolving the issue.

Conclusion

The SMTP banner in cPanel establishes trust and ensures proper email delivery between servers.

When the Reverse DNS does not match the SMTP banner, it can lead to various email delivery issues, including email rejection and spam marking.

To prevent such consequences, it is essential to configure the SMTP banner accurately and ensure alignment with the Reverse DNS.

Following the troubleshooting steps outlined in this guide, you can identify and resolve any SMTP banner issues in cPanel, ensuring seamless email communication and maintaining a positive reputation for your domain’s emails.

So, let’s align those Reverse DNS and SMTP banners for smooth sailing in the email delivery world!