Exim: filtering emails without SPF using Spamassassin

For an Exim mailbox, there are two ways to configure Spamassassin to filter incoming emails from domains without SPF. You willl need:

• install and configure Spamassassin
• install Sieve
• create an email filtering rule

First, make sure you have Spamassassin, Dovecot, and Sieve installed. Under Software configuration - Mail server, install any necessary software, if needed.

Filtering by X-Spam_report

It is recommended to filter by the X-Spam_report header, as it contains precise information about the presence or absence of SPF.

In ispmanager 6 panel, this can be done in the Mail section by selecting the desired mailbox and opening Filter settings from the context menu.

Click Create filter, give it a name, and fill in the condition fields as below:

• Condition — message headers
• Parameter value — X-Spam_report
• Condition — contains
• Values ​​— does not publish an SPF Record

Next, select the action to take on the sorted email. For example, you can save it to a separate SPAM folder.

Filtering by X-Spam_Score

To filter emails without an SPF record by email rating, add the following lines to the /etc/mail/spamassassin/local.cf configuration file to increase the required email rating threshold:

score SPF_NONE 3.0
score SPF_HELO_NONE 1.0

Next, in the ispmanager 6 panel, create a sorting rule in the Mail section by selecting the desired mailbox and opening Filter settings from the context menu.

Click Create filter, give it a name, and fill in the condition fields as below:

• Condition ​​— message headers
• Parameter value ​​— X-Spam_Score
• Condition ​​— matches regex
• Values ​​​​— ^([6-9]|[1-9]|[0-9]+)(\.[0-9]+)?$|^5\.[0-9]*[1-9][0-9]*$

Next, select the action to take on the sorted email. For example, you can save it to a separate SPAM folder.