Block and Allow IP with iptables - simple script

Nov 25, 2009 1 min read #linux #scripting

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As most developers are lazy, I’m a huge fan of scripts. I’ve found myself lately having to add entries to iptables to block a single IP or a small subnet, so I made a quick script to make the job easier on myself.

Usage for both of these is of course really simple. Say 123.1.2.3 is the IP in question:

sudo ./blockip.sh 123.1.2.3
sudo ./allowip.sh 123.1.2.3

bash

Block and allow the IP using iptables with these scripts:

blockip.sh

bash

#!/bin/bash

#blocking iptables
/sbin/iptables -A INPUT -s $1 -j DROP

#saving iptables
/sbin/iptables-save > /etc/sysconfig/iptables

allowip.sh

bash

#!/bin/bash

#allowing iptables
/sbin/iptables -D INPUT -s $1 -j DROP

#saving iptables
/sbin/iptables-save > /etc/sysconfig/iptables