iptables is built on top of netfilter, iptables is the packet alteration framework for Linux 2.4.x and 2.6.x. It is a major rewrite of its predecessor ipchains, and is used to control packet filtering, Network Address Translation (masquerading, portforwarding, transparent proxying), and special effects such as packet mangling.
If you are using SSH then you will sooner or later notice someone trying to hack into your box using dictionary attacks. You can use the iptables module recent to limit a minimum time between new connections from the same IP.
Continue Reading... If you are using SSH then you will sooner or later notice someone trying to hack into your box using dictionary attacks. You can use the iptables module recent to limit a minimum time between new connections from the same IP.
source:http://linuxpoison.blogspot.com/2011/04/135781677519839.html