Let us take a closer look at how to configure SpamAssassin Exim and how to set it up. At Bobcares our Server Management Support services can give you a detailed overview of the process.

What is SpamAssassin?

It is an application under Apache License 2.0. It can filter e-mail spam using content to go with it. SpamAssassin is a powerful email filter that employs a variety of tests to detect bulk spam emails. And it applies tests to email headers and content to group emails using complex methods.

Now let us look at how to set up SpamAssassin in Exim.

UPDATE THE SYSTEM

ssh into the server and run the following command to start a screen session:

screen -U -S exim-spamd

Once we are in a screen session, use yum to update the VPS, as in:

yum update

INSTALL SPAMASSASSIN

The next step to set up the SpamAssassin Exim is to install the Spamassassin. It is available in the CentOS base repository. So we can install it  with yum as shown below:

yum install spamassassin

After installing it, use any editor and modify /etc/mail/spamassassin/local.cf to include the following:

vim /etc/mail/spamassassin/local.cf

required_hits 5
report_safe 0
rewrite_header Subject [SPAM]
required_score 5.0. After this, launch SpamAssassin. Add it to the system’s startup using systemctl.

After that we have to update the SpamAssassin rules using the command line given below:

## sa-update --nogpg

After that, use ss from iproute2 to see if SpamAssassin is listening on localhost (127.0.0.1) on port 783:

Configure EXIM With Spamassassin

The next step is to set up Exim to use Spamassassin to scan and tag junk emails as SPAM. As a result, create a backup of the current Exim setup file by using:

## cp /etc/exim/exim.conf{,.backup-no-spamd}

After that, open exim.conf and insert the following line at the top of the file:

After that, add or remove the spamd_address line as shown below to setup the SpamAssassin in Exim:

## vim /etc/exim/exim.conf
spamd_address = 127.0.0.1 783

Following that, we must include the following in the Exim configuration files ACLs section:

## vim /etc/exim/exim.conf

Avoid Spam Assassin determines whether the message is too big.

accept condition = ${if >={$message_size}{100000} {1}}

add_header = X-Spam-Note. Here the SpamAssassin won’t be present due to the message size.

Allow SpamAssassin to fail or time out before running it. If this occurs, add a warning message and accept the letter. If the SA score exceeds the system threshold, add an X-Spam-Flag: header.

Add score and report headers:

warn add_header = X-Spam-Score: $spam_score ($spam_bar)\n\
X-Spam-Report: $spam_report,

After that, under /etc/exim/filters, add the following Exim system filters:

Then restart Exim to see the changes take effect. This is the final step to set up SpamAssassin in Exim.

## systemctl restart exim
## systemctl status exim

Test Spamassassin After Exim Setup

To test the setup, send a test email to any email account on the email server with the subject:

XJS*C4JDBQADN1.NSBN3*2IDNEN*GTUBE-STANDARD-ANTI-UBE-TEST-EMAIL*C.34X.

And we should see the following lines in the email header:

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Conclusion

To sum up we have learned how to set up SpamAssassin Exim. With the support of our Server management services, we have gone through all of the setup steps.