Port Forwarding With Firewalld

Maciej

2 min readAug 18, 2020

Environment

Host OS: Windows 10
Guest OS: Centos 8

Topology

Thing you want to do

Accessed from the browser on the host OS side with :8080, and port forwarding to the server as :80.

The above figure is hard to understand, but the point is to switch :8080 communication from the host OS side to :80 and send to httpd .

This time, it is forwarding to the same server, but it can be done to another server.

Port forwarding within the same server

firewall-cmd --add-forward-port=port=port-number:proto=tcp|udp|sctp|dccp:toport=port-number

Command example

[root@centos7 vagrant]# firewall-cmd --add-forward-port=port=8080:proto=tcp:toport=80
success

Explanation:

Write the port information perky after--add-forward-port

port=8080 comes from client: :8080
proto=tcp uses tcp as the protocol
toport=80 comes to :80

Command for persisting settings

[root@centos8 vagrant]# firewall-cmd --runtime-to-permanent
success

Persistence can be made by adding--permanent to the command add-forward- … above, but this time it is made permanent from another command.

Command to check the settings

[root@centos8 vagrant]# firewall-cmd --list-all
public (active)
  target: default
  icmp-block-inversion: no
  interfaces: eth0 eth1
  sources:
  services: dhcpv6-client ssh
  ports:
  protocols:
  masquerade: no
  forward-ports: port=8080:proto=tcp:toport=80:toaddr=
  source-ports:
  icmp-blocks:
  rich rules:[root@centos8 vagrant]#

Output will vary by environment.

Port forwarding to another IP

firewall-cmd --add-forward-port=port=port-number:proto=tcp|udp:toport=port-number:toaddr=IP/mask