We have already discussed about the IPTables basics in Linux and also some common usages of it to secure your Linux server. By using iptables you can block particular IP address or a range of IP addresses on your server to protect your server. In this way you can block IPs which are in listed on your secure log for unnecessary login attempts or something like that. That’s why, simply you can secure your server from unwanted connections. To block an IP address from server, you need to add blocking rules to your iptables INPUT chain. The important iptables switches required to perform this actions are;