Install postfix-gld by entering the following commands in the terminal:
sudo apt update sudo apt install postfix-gld
Description:
greylisting daemon for postfix, written in C, uses MySQL
gld stands for GreyList Daemon. gld is a standalone policy delegation server for postfix that implements the greylist algorithm as defined at http://www.greylisting.org
Homepage: http://www.gasmi.net/gld.html
Version: 1.7-8
Section: universe/mail