The next step is to create the Linux kernel. This action opens the kernel configuration with an X-Windows front end, as shown in Figure 8 . Do not forget the dot at the beginning of the filename. Figure 9 shows the recommended configuration parameters for the Linux firewall. After saving the new configuration to the .config file, you can start to compile a new kernel enabled for operation in a Linux firewall.
First use make clean to remove old related binaries before starting the kernel compilation process.
The next step is to create the new dependencies between the various modules with make depend. Next create the modules containing the drivers, with make modules. Finally, compile the kernel itself with make bzImage bzlilo. These steps create two new files under the root directory, called vmlinuz and System.map. The first is the Linux kernel itself, and the second is the information file containing the possible modules available for that kernel.