How to install and configure a firewall in Ubuntu?

@thelma.stanton 

Ubuntu comes with a built-in firewall called UFW (Uncomplicated Firewall). Here are the steps to install and configure UFW:

Step 1: Install UFW

You can install UFW using the following command in the terminal:

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sudo apt-get install ufw

Step 2: Check the status of UFW

Before configuring the firewall, you should check whether it is active or not. You can use the following command to check the status of UFW:

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sudo ufw status verbose

If UFW is not active, you will see the following message:

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Status: inactive

Step 3: Configure UFW

You can configure UFW by adding rules to allow or deny incoming and outgoing traffic. Here are some examples of how to configure UFW:

• Allow SSH traffic:sudo ufw allow ssh
• Allow HTTP traffic:sudo ufw allow http
• Allow HTTPS traffic:sudo ufw allow https
• Deny all incoming traffic:sudo ufw default deny incoming
• Allow all outgoing traffic:sudo ufw default allow outgoing

You can also specify a specific IP address or a range of IP addresses to allow or deny traffic. For example, to allow traffic from the IP address 192.168.1.100, you can use the following command:

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sudo ufw allow from 192.168.1.100

To deny traffic from the IP address 192.168.1.100, you can use the following command:

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sudo ufw deny from 192.168.1.100

Step 4: Enable UFW

Once you have configured UFW, you can enable it using the following command:

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sudo ufw enable

After enabling UFW, you can check the status again to make sure it is active:

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sudo ufw status verbose

That's it! You have successfully installed and configured UFW in Ubuntu.