Sending Email using s-nail on RHEL 9 with Enhanced Security Measures

Sending Email using s-nail on RHEL 9 with Enhanced Security Measures

In Red Hat Enterprise Linux 9 (RHEL 9), sending emails through the command line can be accomplished using s-nail, a feature-rich implementation of the mailx command. This medium will guide you through the process of configuring s-nail to send emails securely using SMTP with STARTTLS and login authentication.

Prerequisites

Before you proceed, ensure that s-nail is installed on your RHEL 9 system:

dnf install s-nail

Configuring s-nail for Secure Email Transmission

Editing the .mailrc Configuration File

To configure s-nail for sending emails securely, you need to edit the .mailrc file located in the root or other user directory:

vi /root/.mailrc

# Please do not forget switch to user For postgres and other user 
su - postgres
vi .mailrc

Add the following configurations to enable STARTTLS, disable SSL/TLS certificate verification, and set SMTP server details along with authentication credentials:

set smtp-use-starttls
set ssl-verify=ignore

set smtp=10.6.120.120:25
#[SMTP-SERVER]:[SMTP-SERVER-PORT]

set smtp-auth=login

set smtp-auth-user=bilgi@itu.edu.tr
# Sender adresses

set smtp-auth-password=password

• smtp-use-starttls: Enables STARTTLS to establish an encrypted connection for SMTP sessions, enhancing email traffic security.
• ssl-verify=ignore: Disables SSL/TLS certificate verification. While this may reduce security, it's set here based on your provided configuration.
• smtp: Specifies the SMTP server address and port.
• smtp-auth: Enables login authentication for SMTP.
• smtp-auth-user and smtp-auth-password: Specifies the email address and password for SMTP authentication.

Save and close the .mailrc file.

Sending a Test Email

Now, you can send a test email using the mailx command with verbose output to reciver:

mailx -v -s "Test Email Subject" -r bilgi@itu.edu.tr ozk17@itu.edu.tr < /root/deneme.txt

• -v: Enables verbose output to display detailed information about the email sending process.
• -s "Test Email Subject": Specifies the subject of the email.
• -r bilgi@itu.edu.tr: Sets the sender email address.
• ozk17@itu.edu.tr: Specifies the recipient email address.
• < /root/deneme.txt: Sends the content of /root/deneme.txt as the email body.

Conclusion

Configuring s-nail on RHEL 9 for sending emails securely involves enabling STARTTLS for encrypted connections, setting SMTP server details, and providing authentication credentials. While disabling SSL/TLS certificate verification may reduce security, it's essential to understand its implications and weigh them against your specific requirements.

By following the steps outlined in this guide, you can send emails securely using s-nail on RHEL 9, ensuring the confidentiality and integrity of your email communications. For more detailed and technical articles like this, keep following our blog on Medium. If you have any questions or need further assistance, feel free to reach out in the comments below and directly.