Firewall Configuration

Configuring The Firewall

Start and enable the firewall

To start and enable the firewall use the commands below

systemctl start firewalld

systemctl enable firewalld

Get an overview

Default Zone

Find the default zone.  The default zone is usually public

firewall-cmd --get-default-zone

Display Allowed Services

Display the allowed services of the zone

firewall-cmd --list-service --zone=external

By default, "public" zone is applied with a NIC and dhcpv6-client and ssh are allowed.

Display Services Defined By Default

To list all service defined by default use the command below

firewall-cmd --get-services

It should give you an output similar to

Add/Remove services

Add or Remove allowed services.  The change will be back after rebooting the system. If you change settings permanently, add the "--permanent" option.

Add/Remove Ports

Add or remove allowed ports

Add/Remove Prohibited ICMP Types

Add or remove prohibited ICMP types