Refresh IPTables to factory Settings - Reset Iptables

https://kerneltalks.com/virtualization/how-to-reset-iptables-to-default-settings

https://upcloud.com/community/tutorials/configure-iptables-centos/

https://forums.centos.org/viewtopic.php?t=68917

https://www.thegeekstuff.com/2011/01/iptables-fundamentals/

 

 So, the structure is: 

 iptables -> Tables -> Chains -> Rules.

IPTABLES 

• Tables
• Chains
• Rules

In our last post, we saw iptables basics, where we learned about how iptables works, what are the policies, and how to configure iptables policies.

While working on iptables, if you get confused about policies and you need to start afresh then you need to reset iptables to default settings. By default, I mean to set accept all policy and flush any existing configured rules from settings.

In this article, we will walk through a set of commands to reset iptables to default settings. This can also be treated as how to reset firewall in Linux like ubuntu, centos, Redhat, Debian, etc. It’s a pretty simple 2 steps process.

Step 1 : Set accept all policy to all connections

Using the below set of commands you will set accept rule for all types of connections.

root@kerneltalks # iptables -P INPUT ACCEPT root@kerneltalks # iptables -P OUTPUT ACCEPT root@kerneltalks # iptables -P FORWARD ACCEPT

This will confirm, iptables gonna accept all requests for all types of connections.

Step 2 : Delete all existing rules.

Using below set of commands, delete your currently configured rules from iptables.

root@kerneltalks # iptables -F INPUT root@kerneltalks # iptables -F OUTPUT root@kerneltalks # iptables -F FORWARD

Or you can do it in single command –

root@kerneltalks # iptables -F

That’s it! Your iptables are reset to default settings i.e. accept all! Now, neatly and carefully design your policies and configure them.