Using `iptables` on Linux

In this video, I show you how to use iptables to firewall inbound traffic on your Linux server or home computer.

Here's some useful commands:

# enable all traffic on localhost
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
# list all rules
iptables -L -n
# accept traffic on HTTP and HTTPS
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j ACCEPT
# set the policy to DROP
iptables -P INPUT DROP

# an extra one not shown in the video: this will allow all outgoing traffic for already established TCP connections. This is important if you limit inbound traffic as well as outgoing traffic.
iptables -A OUTPUT -p tcp --dport 513:65535 --state ESTABLISHED -j ACCEPT

# delete the fifth input rule
iptables -D INPUT 5

[kalyanirajalingham]

Very nice. I like how you use a real life example

[anthonyashford]

6 Years later and this video helped me out a ton! Thanks man!

[dsulvadarius]

You've got an interesting channel and this is a nice video.

[Mono]

Is there a way to throttle bandwidth for specific applications (not ports)? Maybe using iptables or sth else.

[macuser]

What distro are you running on your Linux computer?

[VulcanOnWheels]

Thanks for the explanation, but I was hoping to see how to block specific servers using iptables, assuming that's possible.

[ianhuang]

i accidentally set policy to drop and now i cant connect to ssh help!!!

[abhisarkar]

but nmap doesnot showing open ports how to see

[rocktheworldk]

4K recording? what? how?... *mind explodes*