Fact Sheet on the Linux Firewall Builder

Firewall Builder is a graphical firewall management and configuration tool that supports many open source firewall platforms like Cisco IOS. The Firewall Builder is used primarily on Linux operating systems. This tutorial will show you how to use the Interface objects in Firewall Builder.

Interface Objects
Interface objects are used by firewalls to host objects and cannot exist alone. The specific dialog for the interface object that belongs to the firewall can be described in several parameters. Here is a list of these categories:

Name - The name of the interface object should match up with the name of the firewall machine it represents.

Management interface - When a firewall has many network interfaces, one of them must be allocated as the "management interface," which is used for all communication between Firewall Builder and the specific firewall.

Label - This field is usually not used, but serves the purpose of a descriptive label.
Unprotected interface: an interface that should not assign any access lists or firewall rules.

External Interface: Allocates an interface that connects directly to the Internet.

Regular Interface - This option is used when the interface has an IP address assigned to it.

Address is assigned dynamically - Unlike the regular interface, this option is used when the interface has a dynamic address.

Bridge Port - Use this option to port a bridge firewall.

Unnumbered Interface - Use this option if the specific interface cannot have an IP address.

Security Level - This option is self-explanatory. The security level can be set to External, Internal, or have a numeric value between 0 and 100.

Network Zone - This option is used to set the network zone on Cisco PIX. The dropdown list will show all present network objects. The user will then have the option to choose one of these network objects to command the compiler which network addresses can be reached.

Assigning Policy Rules Using The Interface Object
You can use the Interface Object to assign policy rules. For example, you can drag and drop or copy and past interface objects to the policy rules column to make the firewall correspond.
You can also use the Interface Object with dynamic addresses in policy rules. When an interface has its address assigned dynamically, this means the address is unknown to the Firewall Builder policy compiler when the configuration script is generated. The compiler uses features of the target firewall to fix this.