Firewalls are crucial security solutions to protect computer networks and the internet from dangers and unauthorized access. A firewall is an instrument of computer software or hardware that filters and blocks internet traffic using pre-established rules. Iptables, one of the most widely used firewall tools for Linux systems, is a powerful tool for establishing and administering firewall rules. You need an iptables reset for security.

The first step in doing an iptables reset is to flush the current rules using the “sudo iptables -F” command. Deleting all of the active firewall rules will be the result. The next step is removing previously generated custom chains using the “sudo iptables -X” command. The final step is to run the command “sudo iptables -P” to establish the default policies for the iptables chains.  iptablets-linux

We’ll thoroughly explain how to restart iptables in this article. We will go through how to flush all of the current rules, remove custom chains, create default policies for iptables chains, and save the new iptables rules as we go through the process of resetting iptables. For individuals who are unfamiliar with using firewalls, this procedure might be scary. But with the appropriate instructions, resetting iptables may be a simple and efficient approach to return the firewall settings on the system to their default values. 

See Also: Top 10 Linux Firewall Commands To Increase Your Security [Easy Guide]

Iptables: What is it? 

On a Linux-based system, the use of the firewall tool Iptables is to control network traffic. It is a tool for establishing rules for incoming and outgoing network traffic and is present in most Linux distributions. In iptables, rules are used to match on the origin and destination IP addresses, port numbers, and other criteria to allow or deny traffic.

Iptables operate by keeping track of several chains, which are effectively collections of rules. Iptables evaluate the rules in each chain when a network traffic packet enters the firewall to determine whether to allow or prohibit the traffic. The firewall discards traffic that fits a rule that prevents it. A pack can only pass through if it matches a rule that permits it.

Iptables are a potent tool for controlling network traffic but can also be intricate and challenging. In certain circumstances, an iptables reset is necessary, erasing the current rules and returning the system to its default configuration. This is particularly true if you have changed the regulations and are still determining their potential effects. 

How to configure IP tables

The procedure of doing an iptables reset is very straightforward, but you should proceed carefully to avoid unintentionally blocking crucial network traffic or jeopardizing the security of your system. The actions you must do for configuring iptables in Linux iptables are as follows: 

 Step 1: Confirm installation of iptables. 

Ensure the installation of iptables on your system before attempting to reset it. Most Linux distributions come with iptables by default, but you must first install them if yours does not. To check if iptables is installed on your system, enter the subsequent command into your terminal: iptables-L sudo sudo-iptables-l-terminal-output

If you have already installed iptables, you can use the command “iptables -L” to display a list of active rules. If iptables is not installed, an error message will appear indicating an unrecognized command.

Step 2: Make a backup of your current iptables rules. 

It’s crucial to back up your current rules before resetting iptables so that you can restore them if required. saving-Iptables-rulesThe iptables-save command may help store the current rules in a file. A file named iptables.backup will save the existing rules by the subsequent command: iptables. Backup> sudo iptables-save. You may then use this to back up your current iptables rules. 

Step 3: Delete all iptables rules

After backing up your current rules, you can proceed with flushing all of the current iptables rules. All existing rules will be removed and the default settings will be reinstated by doing this. You may carry out this with the command: iptables -F sudo output-chain-iptablet-f

 Since this command will clear iptables rules, all incoming and outgoing network traffic will be, by default, permitted. You should move carefully and ensure you have a plan for re-establishing the essential regulations because this might jeopardize your system’s security. 

See Also: How To Block An IP Address: Top 5 Ways [Easy Methods]

 Step 4: Dispose of all customized iptables chains 

You could have made custom chains in addition to the chains that iptables create by default to control your network traffic. Before resetting iptables, removing any custom chains you may have built is crucial to ensure they won’t conflict with the default configuration. The following command can be of use to remove a custom chain: sudo iptables -X [chain-name]. iptable-rulesChange the [chain-name] to the name of the custom chain you want to remove. 

Step 5: Configure the iptables chains’ default policies 

After flushing the current rules and removing custom chains, the requirement is to set default policies for the iptables chains. Default rules determine whether incoming or outgoing network traffic is allowed or denied by default. You can issue the following commands to establish default policies: 

  • sudo iptables -P INPUT ACCEPT  
  • sudo iptables -P OUTPUT ACCEPT  
  • sudo iptables -P FORWARD ACCEPTpolicy accept.

These instructions change the INPUT, OUTPUT, and FORWARD chains’ default policies to ACCEPT. They result in the permission of all incoming, outgoing, and forwarded traffic. Additionally, you may set the default policy to DROP, which will automatically stop all traffic. 

Step 6: Save the changed iptables rules. 

You must preserve the updated rules after returning iptables to their standard configuration for them to survive reboots. Save the updated rules to a file using the iptables-save command to do this. The subsequent command will save the updated rules to a file named iptables. Restore: sudo iptables-save > iptables.restore. saving-changed-Iptables-rulesThe updated iptables rules will be saved in a file you can access later. 

 Step 7: Start up your network services again. 

If you want to ensure the restoration of your system’s network connectivity after resetting iptables, you should restart your network services. restart_network_list_serviceYou may carry out this with the command: Restart network. service with sudo. This command will restart your system’s network service, enabling network connectivity. 


Why would I want to reset my iptables configuration?

You should execute an iptables reset for a variety of reasons. For instance, you could have misconfigured your firewall rules, which resulted in connectivity problems, or you might wish to start again after experimenting with various firewall setups.

Will all of my current firewall rules be deleted if I reset IPTables?

If you reset iptables, it will delete your current firewall rules, including any custom chains you may have created.

How can I tell if my computer is running iptables or another firewall application?

Run the following command to see if iptables is installed on your system: Sudo iptables -L. This command returns an error if iptables is not installed on your system. In such a situation, you could utilize a firewall or another application.

How can I verify my system's safety after resetting the iptables?

You should verify your system's firewall rules after resetting iptables and re-establish any necessary rules to guarantee that your system stays safe. Additionally, you should watch for any strange behavior on your system and consider adding extra security safeguards like intrusion detection systems or network monitoring tools.


To guarantee no jeopardy to your system’s safety and network connectivity, you should take caution and ensure you have a strategy for re-establishing the appropriate regulations. An effective technique to reset the firewall settings on your machine to their default values is to do an iptables reset. You may reset your iptables securely and efficiently by following the instructions in this article, allowing you to start again with a blank slate.

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Avatar for Athima Chansanchai
Athima Chansanchai: News reporter, Microsoft News Center. Formerly: Microsoft technical writer (Word for iPad) & Tech-Sci blogger. Writes, edits consumer tech content.