How To Install exim-greylist on CentOS 8
Introduction
In this tutorial we learn how to install exim-greylist on CentOS 8.
What is exim-greylist
This package contains a simple example of how to do greylisting in Exim’s ACL configuration. It contains a cron job to remove old entries from the greylisting database, and an ACL subroutine which needs to be included from the main exim.conf file. To enable greylisting, install this package and then uncomment the lines in Exim’s configuration /etc/exim.conf which enable it. You need to uncomment at least two lines – the ‘.include’ directive which includes the new ACL subroutine, and the line which invokes the new subroutine. By default, this implementation only greylists mails which appears ‘suspicious’ in some way. During normal processing of the ACLs we collect a list of ‘offended’ which it’s committed, which may include having SpamAssassin points, lacking a Message-ID host, etc. There are examples of these in the default configuration file, mostly commented out. These should be sufficient for you to you trigger greylisting for whatever ‘offences’ you can dream of, or even to make greylisting unconditional.
We can use yum or dnf to install exim-greylist on CentOS 8. In this tutorial we discuss both methods but you only need to choose one of method to install exim-greylist.
Install exim-greylist on CentOS 8 Using dnf
Update yum database with dnf using the following command.
sudo dnf makecache --refresh
The output should look something like this:
CentOS Linux 8 - AppStream 43 kB/s | 4.3 kB 00:00
CentOS Linux 8 - BaseOS 65 kB/s | 3.9 kB 00:00
CentOS Linux 8 - ContinuousRelease 43 kB/s | 3.0 kB 00:00
CentOS Linux 8 - Extras 23 kB/s | 1.5 kB 00:00
CentOS Linux 8 - FastTrack 40 kB/s | 3.0 kB 00:00
CentOS Linux 8 - HighAvailability 36 kB/s | 3.9 kB 00:00
CentOS Linux 8 - Plus 24 kB/s | 1.5 kB 00:00
CentOS Linux 8 - PowerTools 50 kB/s | 4.3 kB 00:00
Extra Packages for Enterprise Linux Modular 8 - x86_64 13 kB/s | 9.2 kB 00:00
Extra Packages for Enterprise Linux 8 - x86_64 24 kB/s | 8.5 kB 00:00
Metadata cache created.
After updating yum database, We can install exim-greylist using dnf by running the following command:
sudo dnf -y install exim-greylist
Install exim-greylist on CentOS 8 Using yum
Update yum database with yum using the following command.
sudo yum makecache --refresh
The output should look something like this:
CentOS Linux 8 - AppStream 43 kB/s | 4.3 kB 00:00
CentOS Linux 8 - BaseOS 65 kB/s | 3.9 kB 00:00
CentOS Linux 8 - ContinuousRelease 43 kB/s | 3.0 kB 00:00
CentOS Linux 8 - Extras 23 kB/s | 1.5 kB 00:00
CentOS Linux 8 - FastTrack 40 kB/s | 3.0 kB 00:00
CentOS Linux 8 - HighAvailability 36 kB/s | 3.9 kB 00:00
CentOS Linux 8 - Plus 24 kB/s | 1.5 kB 00:00
CentOS Linux 8 - PowerTools 50 kB/s | 4.3 kB 00:00
Extra Packages for Enterprise Linux Modular 8 - x86_64 13 kB/s | 9.2 kB 00:00
Extra Packages for Enterprise Linux 8 - x86_64 24 kB/s | 8.5 kB 00:00
Metadata cache created.
After updating yum database, We can install exim-greylist using yum by running the following command:
sudo yum -y install exim-greylist
How To Uninstall exim-greylist on CentOS 8
To uninstall only the exim-greylist package we can use the following command:
sudo dnf remove exim-greylist
exim-greylist Package Contents on CentOS 8
/etc/cron.daily/greylist-tidy.sh
/etc/exim/exim-greylist.conf.inc
/etc/exim/mk-greylist-db.sql
/var/spool/exim/db/greylist.db
References
Summary
In this tutorial we learn how to install exim-greylist on CentOS 8 using yum and dnf.