Tips - How to disable iptables firewall temporarily
Learn how to disable iptables firewall in Linux temporarily for troubleshooting purpose. Also learn how to save policies and how to restore them back when you enable firewall back.
Richard Balog©
Sometimes you have the requirement to turn off iptables firewall to do some connectivity troubleshooting and then you need to turn it back on. While doing it you also want to save all your firewall policies as well. In this article, we will walk you through how to save firewall policies and how to disable/enable iptables firewall.
Save iptables policies
The first step while disabling iptables firewall temporarily is to save existing firewall rules/policies. iptables-save command lists all your existing policies which you can save in a file on your server.
sudo iptables-save > /root/firewall_rules.backup
Stop/disable iptables firewall
For older Linux kernels you have an option of stopping service iptables with service iptables stop but if you are on the new kernel, you just need to wipe out all the policies and allow all traffic through the firewall. This is as good as you are stopping the firewall.
Use below list of commands to do that.
sudo iptables -F
sudo iptables -X
sudo iptables -P INPUT ACCEPT
sudo iptables -P OUTPUT ACCEPT
sudo iptables -P FORWARD ACCEPT
Where :
-F: Flush all policy chains-X: Delete user defined chains-PINPUT/OUTPUT/FORWARD: Accept specified traffic
Once done, check current firewall policies. It should looks like below which means everything is accepted (as good as your firewall is disabled/stopped)
sudo iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
Restore firewall policies
sudo iptables-restore < /root/firewall_rules.backup
Check if all policies are back in iptables firewall configurations :
sudo iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination
f2b-sshd tcp -- anywhere anywhere multiport dports ssh
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
DROP all -- anywhere anywhere ! match-set whitelist4 src
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
Chain LOGGING (0 references)
target prot opt source destination
Chain f2b-sshd (1 references)
target prot opt source destination
RETURN all -- anywhere anywhere
