Creating a Firewall for Your Ubuntu Desktop

[Dangertux]

Generally speaking if you're using an application such as thunderbird to check your gmail or whatever as opposed to the web based interface those services provide you will know the ports it uses (since you likely configured it) If you didn't configure it you can consult that services documentation as it will usually point out what ports need to be used to communicate with the service.

As a side note, not related to the original two questions asked, I don't particularly condone use of an additional email client, surface area and all. It's adding another application to the mix that can be exploited, opening more avenues of communication for malicious code to utilize etc.

That being said, I'll add the gmail ports to the list as it is a popular service.

[ubun3]

well this takes a long time to learn.
going back to windows I feel safer at least I do not have to configure all these

[Dangertux]

well this takes a long time to learn.
going back to windows I feel safer at least I do not have to configure all these

There are three different methods illustrated you only have to use 1 of them, they all do the same.

As far as Windows goes you should really be doing the same there, basically firewall methodology is not different between platforms. By default neither Windows firewall, nor commercial products like Zone Alarm come in a particularly secure configuration. If you want to make a configuration equivalent to a default Windows Firewall simply do the following.

sudo ufw enable

Done.

Hope this helps.

[sammiev]

Hi Dangertux, I like to thank you for a well written thread. I checked a lot of my settings with yours as I did it cold and now I feel much better. Keep up the great work!

[Dangertux]

Hi Dangertux, I like to thank you for a well written thread. I checked a lot of my settings with yours as I did it cold and now I feel much better. Keep up the great work!

Glad it was helpful. Thanks for the encouragement

[BigCityCat]

Need help with my network wireless epson printer. Working on the network with firewall off. Not working with firewall on. Is it just a matter of ports?

[Dangertux]

Need help with my network wireless epson printer. Working on the network with firewall off. Not working with firewall on. Is it just a matter of ports?

This could be several issues, since you didn't mention the model of your printer you need to consult the documentation. If it mentions the ports that must be utilized make sure you allow them. If it still does not work after that you may need to enable IGMP multicast traffic (your documentation should tell you this). Though none of these settings should have effected Ubuntu's default policy on that (except maybe the iptables method if you're using that let me know)

Hope this helps.

[BigCityCat]

I can't find anything on ports. It's a epson stylus nx 420. I have 631 allowed so I don't think it's ports.

tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 1308/cupsd
tcp 0 0 0.0.0.0:17500 0.0.0.0:* LISTEN 1867/dropbox
tcp 0 0 192.168.1.71:45378 76.13.117.181:80 ESTABLISHED 1768/gnome-shell
tcp 38 0 192.168.1.71:53654 199.47.217.173:443 CLOSE_WAIT 1867/dropbox
tcp 38 0 192.168.1.71:42710 107.20.249.148:443 CLOSE_WAIT 1867/dropbox
tcp 0 0 192.168.1.71:45944 199.47.216.147:80 ESTABLISHED 1867/dropbox
tcp 0 0 192.168.1.71:59766 209.191.70.53:80 ESTABLISHED 1768/gnome-shell
tcp 0 0 192.168.1.71:42629 98.136.48.46:5050 ESTABLISHED 2055/telepathy-haze
tcp6 0 0 :::5298 :::* LISTEN 2094/telepathy-salu
tcp6 0 0 ::1:631 :::* LISTEN 1308/cupsd
udp 0 0 0.0.0.0:68 0.0.0.0:* 1459/dhclient
udp 0 0 0.0.0.0:57913 0.0.0.0:* 933/avahi-daemon: r
udp 0 0 0.0.0.0:17500 0.0.0.0:* 1867/dropbox
udp 0 0 0.0.0.0:5353 0.0.0.0:* 933/avahi-daemon: r
udp6 0 0 :::49284 :::* 933/avahi-daemon: r
udp6 0 0 :::5353 :::* 933/avahi-daemon: r

[Dangertux]

I can't find anything on ports. It's a epson stylus nx 420. I have 631 allowed so I don't think it's ports.

Are you allowing cupsd input and output? Also are you using ufw or...?


If you're using UFW/GUFW you might try doing the following

sudo ufw allow out to 224.0.0.0/4

That might fix your issue.

[lambcrazy]

all these things that are described are increasing my interest about the ubuntu . i am trying to install the ubuntu on my system .. i will try all these methods on my system .. .