How To Install postgrey on CentOS 8
Introduction
In this tutorial we learn how to install postgrey on CentOS 8.
What is postgrey
Postgrey is a Postfix policy server implementing greylisting. When a request for delivery of a mail is received by Postfix via SMTP, the triplet CLIENT_IP / SENDER / RECIPIENT is built. If it is the first time that this triplet is seen, or if the triplet was first seen less than 5 minutes, then the mail gets rejected with a temporary error. Hopefully spammers or viruses will not try again later, as it is however required per RFC.
We can use yum or dnf to install postgrey on CentOS 8. In this tutorial we discuss both methods but you only need to choose one of method to install postgrey.
Install postgrey 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 postgrey using dnf by running the following command:
sudo dnf -y install postgrey
Install postgrey 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 postgrey using yum by running the following command:
sudo yum -y install postgrey
How To Uninstall postgrey on CentOS 8
To uninstall only the postgrey package we can use the following command:
sudo dnf remove postgrey
postgrey Package Contents on CentOS 8
/etc/postfix/postgrey_whitelist_clients
/etc/postfix/postgrey_whitelist_clients.local
/etc/postfix/postgrey_whitelist_recipients
/etc/sysconfig/postgrey
/usr/lib/systemd/system/postgrey.service
/usr/sbin/postgrey
/usr/sbin/postgreyreport
/usr/share/doc/postgrey
/usr/share/doc/postgrey/Changes
/usr/share/doc/postgrey/README
/usr/share/doc/postgrey/README.Fedora
/usr/share/doc/postgrey/README.exim
/usr/share/licenses/postgrey
/usr/share/licenses/postgrey/COPYING
/usr/share/man/man8/postgrey.8.gz
/var/spool/postfix/postgrey
References
Summary
In this tutorial we learn how to install postgrey on CentOS 8 using yum and dnf.