Firewalld
Firewalld is a linux firewall application.
Installation
You can easily install firewalld through apt
apt install firewalld
Zones
You can list zones with the following command
firewall-cmd --get-zones
block dmz drop external home internal public trusted work
You list what services are associated what a zone, if you don’t speceified what zone it will query the default zone
firewall-cmd --list-all
public
target: default
icmp-block-inversion: no
interfaces:
sources:
services: dhcpv6-client ssh
ports:
protocols:
forward: yes
masquerade: no
forward-ports:
source-ports:
icmp-blocks:
rich rules:
You can also specify the zone
firewall-cmd --zone=external --list-all
external
target: default
icmp-block-inversion: no
interfaces:
sources:
services: ssh
ports:
protocols:
forward: yes
masquerade: yes
forward-ports:
source-ports:
icmp-blocks:
rich rules:
Allow and deny port
You can allow a port with the following command.
firewall-cmd --add-port=2252/udp
You can allow it permanently by adding --permanent as follows.
firewall-cmd --permanent --add-port=2252/udp
If you want to remove it later you can do it with the following command.
firewall-cmd --permanent --remove-port=2252/udp