How to disable the iptables firewall in Linux

Q. Quick question: I need to disable firewall in Linux for testing purpose. I’m using CentOS 4.4. How do I disable the firewall in Linux?

A. A Linux firewall is software based firewall that provides protection between your server (workstation) and damaging content on the Internet or network.

It will try to guard your computer against both malicious users and software such as viruses/worms.
Task: Disable / Turn off Linux Firewall (Red hat/CentOS/Fedora Core)

Type the following two commands (you must login as the root user):
# /etc/init.d/iptables save
# /etc/init.d/iptables stop
Task: Enable / Turn on Linux Firewall (Red hat/CentOS/Fedora Core)

Type the following command to turn on iptables firewall:
# /etc/init.d/iptables start
Other Linux distribution

If you are using other Linux distribution such as Debian / Ubuntu / Suse Linux etc, try following generic procedure.

Save firewall rules
# iptables-save > /root/firewall.rules
OR
$ sudo iptables-save > /root/firewall.rules

Now type the following commands (login as root):
# iptables -X
# iptables -t nat -F
# iptables -t nat -X
# iptables -t mangle -F
# iptables -t mangle -X
# iptables -P INPUT ACCEPT
# iptables -P FORWARD ACCEPT
# iptables -P OUTPUT ACCEPT

To restore or turn on firewall type the following command:
# iptables-restore < /root/firewall.rules
GUI tools

If you are using GUI desktop firewall tools such as 'firestarter', use the same tool to stop firewall.
System > Administration > firestarter > Click on Stop Firewall button:

you can get the status of iptables with the following

service iptables status

service iptables help gives:

Usage: /etc/init.d/iptables {start|stop|restart|condrestart|status|panic|save}

IPTables is actually "blank" until another program (like Firestarter) acts on them. To list the current rules

Code:
sudo iptables -L -v

If its blank (except for headers like CHAIN INPUT) then iptables isn't doing a damn thing.