Open the rules.v4 file in your preferred text editor. To implement the firewall policy and framework, you’ll edit the /etc/iptables/rules.v4 and /etc/iptables/rules.v6 files. Afterwards, we will explain the general strategy and how these rules could be implemented using the iptables command instead of modifying the file. Implementing the Basic Firewall Policy (The Quick Way)įor the purpose of getting up and running as quickly as possible, we’ll show you how to edit the rules file directly and copy and paste the finished firewall policy.

If your services do not leverage IPv6, it’s safer to block access entirely, as will be demonstrated in this guide. This guide assumes that you are not actively using IPv6 on your server. For the netfilter-persistent command, the IPv4 rules are written to and read from /etc/iptables/rules.v4, and the IPv6 rules are stored in /etc/iptables/rules.v6.

The rules are stored in separate tables and chains. For IPv6 traffic, a separate companion tool called ip6tables is used. The iptables command only handles IPv4 traffic. A Note About IPv6 in this Guideīefore we get started, we’ll briefly discuss IPv4 vs IPv6. Next, you’ll edit the generated rules files.

Please note that you’ll be running the netfilter-persistent command to execute the iptables persistent firewall service. This allows you to save your rule sets and have them automatically applied at boot:ĭuring the installation, you’ll be asked whether you want to save your current rules, select. Now install the iptables-persistent package. Installing the Persistent Firewall Serviceīegin by updating the local package cache: You can follow this guide to get a better idea of what to consider.

You can do this by following all the steps outlined in our Ubuntu 20.04 initial server setup guide, except for Step 4, since we will be setting up the firewall in this tutorial.Īdditionally, we recommend reviewing the firewall policies you wish to implement. To complete this tutorial, you will need access to an Ubuntu 20.04 server with a non- root user configured with sudo privileges. This firewall will focus primarily on providing reasonable defaults and establishing a framework that encourages extensibility. In this guide, you’ll learn how to construct a firewall that can be the basis for more complex rule sets. Firewalls like iptables also allow you to have a say about the structural framework in which your rules are applied. A large part of that is deciding on the individual rules and policies that will enforce traffic restrictions to your network. Implementing a firewall is an important step in securing your server.

Ubuntu iptables