Ufw or ‘uncomplicated firewall’ is a really nice tool that allows you to easily manage ‘iptables’ firewall in Linux with a bit more user friendly frontend instead of ‘iptable’ chains and rules.

   It’s included in the most recent version of Debian and Ubuntu and we’ll start with a simple example – how to open or restrict SSH access to your cloud server.

   To allow the SSH port:

   

       ufw allow ssh

   or

   

       ufw allow 22/tcp

   This will open the SSH port ( TCP 22 ) to the entire world.

   Your cloud server is a public machine and you might want to protect it a bit better than being open to the whole Internet. To restrict the SSH access from only one IP address you can do:

   

       ufw allow from your_ip_address to any port 22

   for example

   

       ufw allow from 78.130.176.1 to any port 22

   You can also allow SSH access to you server from a range of addresses using the network slash notation:

   

       ufw allow from 78.130.176.0/24 to any port 22

   Before we are ready to go with your new firewall setup with ‘ufw’ we can check if it’s enabled by:

   

       ufw status

   and eventually if you get “status: inactive” enable it:

   

       ufw enable

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