Configure UFW on Ubuntu

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Installation of UFW

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UFW is already installed on Ubuntu 18.04. You can verify it from here

which ufw

Output:

 root@vps:~#  which ufw
 /usr/sbin/ufw

Enable/Disable/Reload UFW

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Enable UFW

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Run the command below to activate the firewall

ufw enable

Disable UFW

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Run the command below to activate the firewall

ufw disable

Reload UFW

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Run the following command to turn off the firewall

ufw reload

If you don’t receive output, you need to install UFW. Please refer the following commands.

sudo apt-get install ufw

Allow/Deny port

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Allow port

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Run the command below to allow traffic on a specific port (example: port 80 for HTTP):

ufw allow 80/tcp

Change the port which you want to open.

Deny Port

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Run the following command to block/deny traffic on a specific port

ufw deny 80

Change the port that you want to deny

Check Status of UFW

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Run the following command to check whether UFW is active and view current rules

ufw status

Listing Rules

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Run the following command to display rules in a numbered format (useful for managing rules)

ufw status numbered

Output:

root@vps:~# ufw status numbered
Status: active

  To                         Action      From
  --                         ------      ----
 [ 1] 80/tcp                     ALLOW IN    Anywhere
 [ 2] 80                         DENY IN     Anywhere
 [ 3] 80/tcp (v6)                ALLOW IN    Anywhere (v6)
 [ 4] 80 (v6)                    DENY IN     Anywhere (v6)

Removing rules

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First, check the status of UFW using the following command.

ufw status numbered

Output:

root@vps:~# ufw status numbered
Status: active

  To                         Action      From
  --                         ------      ----
 [ 1] 80/tcp                     ALLOW IN    Anywhere
 [ 2] 80                         DENY IN     Anywhere
 [ 3] 80/tcp (v6)                ALLOW IN    Anywhere (v6)
 [ 4] 80 (v6)                    DENY IN     Anywhere (v6)

This command will show the rules with numbers

Now remove the rule using the following command(Replace the 1 with the rule number which you want to remove)

ufw delete 1

Output:

 root@vps:~# ufw delete 1
 Deleting:
  allow 80/tcp
 Proceed with operation (y|n)? y
 Rule deleted
 root@vps:~#