This comprehensive Linux guide expects that you run the following commands as root user but if you decide to run the commands as a different user then ensure that the user has
sudoaccess and that you precede each of the privileged commands with
A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted internal network and untrusted external network, such as the Internet.
The firewall is suggested to be kept enabled on your system, but in some cases, you might need to disable it. This tutorial will guide you how to disable/enable your firewall on your Ubuntu 18.04.
Checking Your Firewall Status
To check whether your firewall is enabled or disabled, you can run the following command:
[email protected]:~$ ufw status Status: active
This shows that the firewall is enabled.
If you want more verbose output of the status of the firewall, you can use the command like below:
[email protected]:~$ ufw status verbose
Disabling The Firewall
You can disable the firewall by running the following command
[email protected]:~$ ufw disable Firewall stopped and disabled on system startup
Resetting Firewall Rules
If you disable the firewall using the above command, the firewall will be disabled but the rules will not be deleted. If you want to delete those firewall rules too, you can reset the firewall by running the following command
[email protected]:~$ ufw reset Resetting all rules to installed defaults. This may disrupt existing ssh connections. Proceed with operation (y|n)? y Backing up 'user.rules' to '/etc/ufw/user.rules.20190122_115214' Backing up 'before.rules' to '/etc/ufw/before.rules.20190122_115214' Backing up 'after.rules' to '/etc/ufw/after.rules.20190122_115214' Backing up 'user6.rules' to '/etc/ufw/user6.rules.20190122_115214' Backing up 'before6.rules' to '/etc/ufw/before6.rules.20190122_115214' Backing up 'after6.rules' to '/etc/ufw/after6.rules.20190122_115214'
Enabling The Firewall
If your firewall is disabled, you can run the following command to enable it:
[email protected]:~$ ufw enable Command may disrupt existing ssh connections. Proceed with operation (y|n)?y Firewall is active and enabled on system startup