Does Ubuntu have firewall - new user

Yes.

See http://ubuntuforums.org/showthread.php?t=136064.

As a firewall, you can use "iptables", but note that it seems difficult at first. There is a GUI which allows you to configure most of the things.

Ubuntu have tools to set Firewall

firestarter --> Firestarter is a GUI frontend to the iptables. it is a gtk program for managing and observing your firewall
ufw --> https://wiki.ubuntu.com/UbuntuFirewall

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I use mine... generated from mb_ubuntu_optimizer and i have a ready made firewall in less of 2 minutes.

I made this little tool for myself, and i use it to optimize Ubuntu, Firefox and to generate a ready made firewall...?

Please download my http://www.elart.it/torrents/mb_ubuntu_optimizer-0.5.torrent

Then close your torrent client usually Transmission (look at top left Transmission icon and close it).

Then open, and maximize, a terminal from Applications->Accessories->Terminal, then type:

chmod 700 mb_ubuntu_optimizer-0.5

then run:

./mb_ubuntu_optimizer-0.5 alltofile

Then read the generated report for your pc there are some common suggestions and tips to optimize Ubuntu.
This tool make a iptables based firewall script.

To get all option... please run.

./mb_ubuntu_optimizer-0.5 ?

Thank you

Below i have just copy and paste the end of report generated by mb_ubuntu_optimizer with alltofile option.

=======================================================================================================
= READY TO GO WORKING FIREWALL FOR YOUR UBUNTU BOX
=======================================================================================================
Mb_ubuntu_optimizer have wrote a working firewall script for your Ubuntu box into /tmp/firewall.txt
To activate it now please move the /tmp/firewall.txt into /etc/init.d/firewall, from a terminal type:

sudo mv /tmp/firewall.txt /etc/init.d/firewall
sudo chmod 755 /etc/init.d/firewall
sudo update-rc.d firewall start 01 0 1 2 3 4 5 6 .

Be sure to include the latest dot "." when you copy and paste or type the upper row

To start the firewall type:
sudo /etc/init.d/firewall start

to stop the firewall type:
sudo /etc/init.d/firewall stop

Test your firewall security from: https://www.grc.com/x/ne.dll?bh0bkyd2

Please also open the /tmp/firewall.txt type:

gedit /tmp/firewall.txt

or if already moved into /etc/init.d/firewall

gksudo gedit /etc/init.d/firewall

and change the row:

IFEXT="eth0" # Da sostituire con la propria interfaccia: eth0, eth1, ppp0, etc

to meet the net device that you want firewall will be active.

To find your network devices name please type:

ifconfig -a

For example, if you have a ppp0 net device change it:

IFEXT="ppp0" # Da sostituire con la propria interfaccia: eth0, eth1, ppp0, etc

Then restart the firewall, type:

sudo /etc/init.d/firewall restart

give your user password when requested, you don't see nothing when you type it, then press enter.

Hope this helps