NB: This tutorial has worked on Centos 6,7,8 and 9
To begin the process, we will start by installing gcc, this is a compiler that will be used for the compilation of the source files.
Centos Allow FTP: FTP needs to be allowed through the firewall for the service to work. Run the command “firewall-cmd –add-service=ftp –permanent” if running centos 7,8 or 9. This will add FTP with its port numbers. Reloard the firewall so that this can take effect by running the command “firewall-cmd –reload”.
For centos 6 and below, add ports 20 and 21 on the source and destination ports. This should be done for the INPUT and OUTPUT chains.
This should allow centos access to FTP including other systems. With this done, we can then install the proftpd service knowing that ports 20 and 21 are enabled.