How to temporarily stop iptables on Ubuntu

iptables is not a service, but a facility inside the kernel. That is why you can't stop it.

If you ever need to stop iptables quickly, here's my suggestion:

1. Configure your iptables to completion.

2. Save the configuration first: iptables-save > /etc/iptables.conf

3. Flush the iptables, and configure it 'open':

• All policies set to ACCEPT
• Configure all necessary NATs for your sysadmin to work
• If you use Policy-Based Routing in the mangle table, also configure it as necessary

4. Save the 'open' ruleset: iptables-save > /etc/open-iptables.conf

Now, whenever you need to quickly 'disable' iptables, do:

cat /etc/open-iptables.conf | iptables-restore.

After that, 're-enable' iptables using:

cat /etc/iptables.conf | iptables-restore

( iptables-restore < /etc/open-iptables.conf might also work; but I've read somewhere else that sometimes it doesn't work )

ADD: Newer versions of iptables-restore can directly read from a file. So the above commands can be simplified to:

iptables-restore /etc/open-iptables.conf
iptables-restore /etc/iptables.conf

respectively.