How to create inbound rules in Ubuntu Firewall with Firestarter
Inbound rules allow you to filter all incoming connections. By default, all uninvited incoming connections are turned away. Creating an inbound rule effectively allows you to create a "hole" in the firewall for certain types of connection to get through, as needed by particular programs. This can be useful if you run file sharing software on your computer, for example, such as Transmission (Applications > Internet), that uses BitTorrent to share files.
Additionally, you can choose to let some inbound connections through, but only if they originate on the local network (i.e. within a particular IP address range). This can be useful in the case of shared folders, for example, where other computers in your workplace or home may wish to access files on your computer.
Here are the steps required to create an in-bound rule:
1. Start the Firestarter configuration program, if it isn't already running, by clicking System > Administration > Firestarter. You'll need to type your password when prompted.
2. Click the Policy tab in the program window, and ensure Inbound Traffic Policy is selected in the Editing dropdown list.
3. Under the Allow Service heading in the lower-half of the program window, right-click and select Add Rule from the menu that appears.
4. In the dialog box that appears, select from the Name dropdown list the type or program that you’d like to allow through the firewall. For example, to allow BitTorrent connections, select that in the list. To let others access shared folders on your computer, select Samba (SMB). Note that the Port field will be automatically filled in once you make your selection. You can edit this if you wish, but there should be no need.
5. If the rule relates to inbound connections from the Internet, ensure the Anyone radio button is selected under the When The Source Is heading.
6. To limit the type of incoming connection to the local network, and not the entire Internet, click the IP, Host or Network radio button. You'll then need to find out the network range that your computer is part of. To do so, right-click the NetworkManager icon at the top-right of the screen, and select Connection Information. Look in the IP Address line within the dialog box that appears, and make a note of the first three numbers. On my test PC, this line read 192.168.1.5, so I made a note of 192.168.1.
7. Back in Firestarter's rule creation dialog box, type the numbers, followed by a period, then a zero. So, in my case I typed 192.168.1.0. Then add a forward slash, and type 24. On my test PC the entire line read 192.168.1.0/24.
8. Once done, click the ADD button, and then the APPLY POLICY button on the toolbar. Then close Firestarter.
9. However, if you're adding a rule to allow access to Samba shared folders on the computer, another step is necessary to let other computers "see" the shared resources across the network. Click Edit > Preferences within Firestarter and, on the left of the dialog box that appears, click the Advanced Options entry in the list. Remove the check from Block Broadcast From External Network. Click ACCEPT when done.
The new rule will take effect immediately. To delete it at a later stage, start Firestarter, right-click the rule, and click Remove Rule. Then click the APPLY POLICY button.
Tags: firestarter,firewall,security,network,inbound,NetworkManager
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