How to Build Linux Firewall

Installing iptable:-

                             Linux provides the robust firewall solutions for the client and server computers.  There are many firewall solutions that Linux supports but iptables is considered the best.  It inserts and deletes the rules in the Kernel’s packet filtering table.  By default, Red Hat Linux includes the iptable.  Use the following commands to install and run the iptable in the red hat Linux.

# bzip2 -d iptables-1.2.6a.tar.bz2
# tar -xpf iptables-1.2.6a.tar
# cd iptables-1.2.6a
# make
# make install

Configurations

• Make sure to set the CONFIG_NETFILTER to Y
• Verify that you are running 2.4.x kernel version.

To configuring the iptable you need to be familiar with the following commands.

• --append or –A             Append to chain
• --delete or –D                Delete rule from chain
• --list or –L [chain]        List rules in a chain or all chains
• --flush or –F [chain]    Delete all rules in a chain or all chains

Iptable covers many commands that are required in the firewall system.  It creates the packet filters to allow or deny the traffic based on different criteria.
In the following resources you can find out more information on how to configure the iptable to fulfill your specific requirements.

• Iptables MAN page
• Netfilter/iptables FAQ
• Oskar Andreasson's IPTables Tutorial 1.1.9
• Linux 2.4 Packet Filtering HOWTO   
• MonMotha's IPTables Firewall

Following is the list of the additional firewall solutions that can be used in the Linux.

• Smooth Wall
• Astaro Internet Security
• Coyote Linux personal firewall
• InJoy Firewall Linux
• Shoreline Firewall
• The SINUS Firewall
• Linux Embedded Appliance Firewall