Iptables basic configurations on RHEL 6.x

IPtables on Redhat Enterprise Linux 6.x

Here we will learn iptables packet filtering tool ships along with most RHEL distros. We will concentrate on Filter chain of iptables.

#mkdir -p /root/bin

#cd /root/bin

#vim firewallconf.sh

#!/bin/bash

iptables -F

## Clears all previous rules

iptables -A INPUT -i lo -j ACCEPT

## Allowing all localhost (Local loopback) traffic

iptables -I INPUT -m state --state ESTABLISHED,RELATED -s 192.168.0.0/24 -j ACCEPT

## Allowing all Established and related packets for local network (192.168.0.0 in our case)

iptables -I INPUT -m state --state NEW -s 192.168.0.0/24 -p tcp --dport 22 -j ACCEPT

## Allowing SSH traffic for all new connection 'made' to your local system, only for your local Lan

iptables -A INPUT -j REJECT

## Rejecting all other traffic which is initiated to your local host

<save and exit>

#chmod 755 firewallconf.sh

#./firewallconf.sh

# service iptables save

# iptables -L

<List all written rules in Filter Chain>

# iptables -nvL --line-numbers

<Lists all rules along with all dropped/rejected and accepted packets>