iptables connection tracking
I am looking for some detailed explanation about iptables connection tracking.
krish@raspberrypi:~ $ sudo iptables -I INPUT 1 -m conntrack --ctstate ESTABLISHED -s 192.168.1.69 -p tcp -j ACCEPT
I understand that this command will track the connection state and permit return traffic in the INPUT chain.
Can anyone please give a detailed explanation about this. What does the state RELATED do?