Blocking abusive IP addresses using IPTABLES Firewall in Debian
In one of our previous article we have posted an instructional guide on how to secure your Debian/Ubuntu based VPS using IPTABLES/Netfilter. In the following article we are adding a blacklist to the firewall script which will allow you to block any abusive IP addresses or ranges of IPs in your Debian or Ubuntu based virtual server. What is iptables? It is is a user space application program that allows a system administrator to configure the tables provided by the Linux kernel firewall (implemented as different Netfilter modules) and the chains and rules it stores. Before proceeding any further, make sure you read the article on how to secure/design the firewall in your linux vps. This includes: Flushing the old firewall rules Determining service ports Setting-up default policies Setting-up your firewall rules Saving your firewall rules BLOCKING IPs USING IPTABLES To block some abusive IP address or range of IPs, you can use the following iptables rules: ## iptables -I INPUT -s 1.2.3.4...