Linux Iptables

The term Netfilter/Iptables may sound a bit confusing because of the ‘Netfilter’ tag. To clear the confusion, Both Netfilter and Iptables are related to each other in the sense that Iptables is to user space what Netfilter is to Kernel space. Iptables provides the facility to users to customize and configure the Linux firewall from user space. This firewall is implemented in Linux kernel through the concept of Netfilters. This functionality of Netfilter was added to Linux kernel from version 2.4.x onwards. Prior to this the concept of Ipchains was used but as that had many bugs and shortcomings so the concept of Netfilter/Iptables was developed.