Like
stated security is one of the top priorities, Ubuntu comes in with a
simple non-GUI program called Uncomplicated
Firewall, or
simply ufw.
What
this is basically a simple firewall program that runs on terminal and
has diverse and easy to learn commands to keep your OS secure whilst
retaining normal functionality.
So
go ahead and open a terminal session and type sudo
ufw status
This
shall show firewall active status which should be inactive by
default, also listing any rules that are active
So
then the proper command to activate it would be sudo
ufw enable , to
turn it off it’s pretty much the contrary type sudo
ufw disable
Okay
so let’s play a game, you would like to disable all
incoming/outgoing connections from the internet using your firewall,
simply put in the commands sudo
ufw default deny outgoing and
sudo
ufw default deny incoming ,
try opening a browser and making a connection to a website it will
give the no internet error.
To
reverse this it’s also pretty simple, contrary to
deny
is sudo
ufw default allow outgoing and
sudo
ufw default allow incoming
Now
for basic port opening and blocking, type in these commands sudo
ufw allow <port number>
or sudo
ufw deny <port number>
, you can also use this for IP addresses sudo
ufw allow/deny from <IP address>
If
you make any mistakes inputting the rules, you can remove them using
the delete function: sudo
ufw delete allow <port number> or
for example
sudo ufw delete deny from <IP address> any
further dubiousness and you may type sudo
ufw reset
Furthermore,
this is how firewall status looks like thus far:
Basically
all this is done for the purpose of controlling network activity from
and to your PC, not too complicated huh?
So
let’s uncomplicate things a little further, there exist GUI
versions of this firewall.
Gufw
for example. You
know the drill. Type sudo apt-get install gufw and proceed as normal.
A
GUI version of ufw which allows you to set firewall rules in a much
easier way.
