command linefirewallufw
Even Ubuntu Firewall in running mode , I am not getting the data. may I know why ?
root@ubuntu:~# sudo ufw status numbered
Status: inactive
root@ubuntu:~# service ufw start
start: Job is already running: ufw
root@ubuntu:~# sudo ufw status numbered
Status: inactive
root@ubuntu:~# sudo ufw status verbose
Status: inactive
root@ubuntu:~#
Out of the box, Ubuntu ships with no TCP or UDP ports open, hence the belief that there's no reason to run Uncomplicated Firewall (ufw) by default. I agree, though, that having ufw disabled is a strange decision. My reasoning being that inexperienced users are feasibly going to install things like Samba, Apache and such like as they experiment with the system put before them. If they don't understand the implications of this, they will expose themselves to malicious bevaviour on the internet.
Example - I've got my laptop configured with Samba which is fine in my home network protected with WPA2. But if I take my laptop to a Starbucks, I might not think anything of it, but that laptop is now advertising my shares to all and sundry. With a firewall, I can restrict my samba ports to only my home server or peer devices. No need to worry as much now about who might be trying to connect to my laptop. Same goes for VNC, SSH, or a huge number of other useful services my laptop might be running, or trying to connect to.
Ubuntu takes a very on/off approach to certain elements of security, a philosophy I can't agree with. Security might be technically on or off, but by layering elements of security over one another, you end up with a better system. Sure, Ubuntu's security is good enough for a large number of use cases, but not all.
Bottom line, run ufw. Better safe than sorry.
Uncomplicated Firewall has a number of graphical front ends, but the simplest is Gufw.
sudo apt-get install gufw
Here, I'm allowing all traffic from specific server VLANs in my corporate environment and I've added a rule to allow the necessary ports for a reverse SSH session to bounce off this machine.
There is currently not a way to show the rules you have entered before enabling the firewall via the CLI command. You can inspect the rules files directly however. /lib/ufw/user*.rules contain the rules controlled via the 'ufw' CLI command. Eg:
$ sudo grep '^### tuple' /lib/ufw/user*.rules
This will show output like the following (for the rule added with 'sudo ufw allow OpenSSH):
/lib/ufw/user.rules:### tuple ### allow tcp 22 0.0.0.0/0 any 0.0.0.0/0 OpenSSH - in
The 'tuple' is the shorthand used internally by ufw to keep track of rules, and can be interpreted as one of these:
### tuple ### <action> <proto> <dst port> <dst> <src port> <src> <direction>
### tuple ### <action> <proto> <dst port> <dst> <src port> <src> <dst app name> <src app name> <direction>
It might be useful to be able to add another status command to support this. Please consider filing a bug.
Best Answer
You need to enable the firewall using
After you enable,
sudo ufw status verboseshould show you the following:To check more options use,
ufw helpFor more on ufw logging, see this answer: