How to Reset iptables Rules: A Comprehensive Guide

Introduction

Resetting your iptables rules can be essential when you need to start afresh due to confusion with existing policies. By resetting, you can ensure that all traffic is accepted, removing any previously configured rules.

This guide is applicable to various Linux distributions, including Ubuntu, CentOS, Red Hat, and Debian. It's a straightforward two-step process.

Step 1: Set Accept All Policy

First, you'll need to configure iptables to accept all incoming, outgoing, and forwarded connections.

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

This sets iptables to accept all requests across all connection types.

Step 2: Flush Existing Rules

Next, delete any existing rules currently configured in iptables.

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

Alternatively, you can use a single command to flush all rules:

root@kerneltalks # iptables -F

Conclusion

Your iptables are now reset to their default settings, which accept all traffic. From here, you can carefully design and implement new policies as needed.

Warning: Resetting iptables will open all ports, so ensure to configure appropriate firewall rules based on your security needs.