Introduction
This article is a collection of various guides that outline the options you have available to reduce the amount of spam that arrives at the inbox of your cPanel email accounts.
This guide covers a large number of options available to you. It is NOT required to implement all of these options to have a spam-free experience on cPanel. Each of the individual options listed here would only be enabled to meet your specific spam protection needs.
Procedure
1. Enable BoxTrapper
This may be among the most easily implemented and effective methods for preventing spam from arriving in your inbox.
Can cPanel's BoxTrapper Software Help Reduce Spam? & How to enable BoxTrapper
2. Teach Spam Assassin How to Identify More Spam
This method requires some custom configuration from a systems administrator, as well as active participation from the end-user. This means that you must train the end-user how to teach Spam Assassin about their specific spam. However, this extra effort does a lot to effectively identify spam messages that may be using more clever techniques for bypassing the widely avaialble spam filters for Spam Assassin.
How to teach Spam Assassin to identify more SPAM
3. Reject messages over a certain size
If you find that the majority of problematic spam that you are getting is over a certain size, and the majority of legitimate messages are under that size, you have the ability to configure your server to reject messages over that size threshold.
Restrict Emails based on message size
4. Adjust the weight of individual SpamAssassin rule scores server-wide
If you find that certain incoming spam messages are getting through, but adjusting the weight of a specific rule would help, the following guide explains how to adjust these rules for the entire server:
How to adjust SpamAssassin rule scoring Serverwide
5. Adjust the weight of individual SpamAssassin rules on a per-account basis
If the incoming spam issue is isolated to a single cPanel account, and you do not want to adjust the weight of a SpamAssassin rule for the entire server, you can use the following guide to accomplish this:
How to adjust the weight of a SpamAssassin rule
6. Add an additional custom SpamAssassin ruleset that better fits your server's needs
You have the option to install custom SpamAssassin rulesets if you find one that will aleviate a problem that you're having with spam.
Where can I find additional rule sets for SpamAssassin?
7. Create Custom rule sets for SpamAssassin
If you have the technical skills and motivation to do so, it is possible to craft your own custom rules for SpamAssassin. Please keep in mind that cPanel is not able to provide support for the creation, installation, use, or maintenance of these custom rulesets.
Is it possible to create custom rules for SpamAssassin?
8. Edit the default SpamAssassin score required to mark a message as spam server-wide
If you find that all legitimate mail on the server scores much lower than the current default SpamAssassin score threshold, and some spam messages are also scoring lower than the current default, you can use the following guide to adjust this setting. However, as a general rule, setting the score lower than the default will end up marking more legitimate mail as spam. Lowering this setting is usually only advisable if you have done extensive training for SpamAssassin from Option 2 listed above and you notice that all legitimate mail scores very low.
How to Reject Emails with High Spam Scores
9. Edit the default SpamAssassin score required to mark a message as spam on a per-account basis
This has the same effect as option 8 above, but it is limited to an individual account.
How do I Change the cPanel Account SpamAssassin Default Score?
10. Block messages by subject server-wide
If you find that a common subject is used for spam messages that are making it through to the inbox, you can block these subjects for the entire server with the following guide:
How to block spam/email by subject for the entire server
11. Filter incoming emails by country
If you find that spam is mainly coming from a specific country that your clients do not interact with, you can block those messages with the following guide:
How to filter incoming emails by country
12. Block all incoming emails that originate from a specific domain
If you find that a specific domain is sending a large amount of messages to your server you can block that domain with the following guide:
How to block emails to your server from a specific domain
13. Enable the default or a custom Remote Block List (RBL)
How to manage the default and custom Remote Block Lists on a cPanel server
14. Stop using BackupMX servers or implement a custom spam protection system on those BackupMX servers if you are using BackupMX
Additional Resources
The following are some other general guides related to Spam Assassin in Spam in general: