Configure Firewalls to Protect the FTP Server

Description

By default, firewalld blocks access to the ports used by the web server. To configure firewalld to allow ftp access, run the following command(s):

firewall-cmd --permanent --add-service=ftp

Then run the following command to load the newly created rule(s):

firewall-cmd --reload

Rationale

These settings configure the firewall to allow connections to an FTP server. The first line allows initial connections to the FTP server port. FTP is an older protocol which is not very compatible with firewalls. During the initial FTP dialogue, the client and server negotiate an arbitrary port to be used for data transfer. The ip_conntrack_ftp module is used by iptables to listen to that dialogue and allow connections to the data ports which FTP negotiates. This allows an FTP server to operate on a system which is running a firewall.