There are certain things that a hosting provider or system administrator can do to prevent email abuse on a cPanel server. These include:
1. Improve password strength
Most people don’t want to remember long and complicated email passwords for fear that they may eventually forget it. But as the hosting provider, increasing password length is one of the best ways to ensure that emails aren’t compromised on your server.
By increasing the minimum password length for all users’ mail accounts, hosting providers will be able to lower the probability that a hacker will be able to correctly guess a password.
It is recommended that cPanel users set the default minimum password strength to 50.
2. Enable cPHulk
This is a feature that protects the server against brute force attacks, or a method in which a hacker utilizes an automated system to correctly guess passwords. By enabling cPHulk, system administrators will be able to lower the chance that a hacker will be able to gain access to their servers’ email accounts.
To activate this feature, users simply have to navigate the cPHulk Brute Protection interface of their WHM. This can be done by clicking Home, then Security Center, and then cPHulk Brute Protection.
3. Enable SMTP restrictions
This is another cPanel feature designed to prevent hackers from compromising email accounts in a cPanel server. By enabling the SMTP Restriction features, system administrators can prevent spammers from directly interacting with remote servers. It would also be impossible for them to work around email security settings.
This feature can be enabled by navigating the SMTRP Restrictions interface, clicking Home then Security Center and SMTP Restrictions, before toggling Enable.
4. Limit number of emails sent per domain
This is ideal for hosting providers that cater to users without bulk mailing requirements. Limiting the number of email that each user can send per hour can prevent email abuse because a spammer would only be able to send a limited number of emails from an account. This effectively gives time to the system administrator to find and stop the spammer.
To do this, hosting providers can go to the Tweak Settings interface located in the Mail section of WHM. They can then set the max hourly emails per domain, or the number of email messages that users can send per hour.
5. Setting a max percentage of failed or deferred messages sent per hour
Lastly, server or system administrators can set a maximum percentage of failed or deferred messages that a domain would be able to send per hour.
This can prompt the server to temporarily block outgoing email from a domain. This happens when the percentage of failed or delayed messages out of the total number of sent messages is equal or greater than the percentage specified by the administrator.
These five best practices can go a long way towards avoiding email abuse on a cPanel server.
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