Best Linux firewalls

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In this article, we will talk about the best Linux firewalls in 2023. In addition, we would describe the whole concept and every helpful detail that you better know about these security solutions. Keep along with us!

What is a firewall?

A firewall is a network security program which controls incoming and outgoing connections based on many rules that are set. Simply put, it is a wall between your computer and the outside network that prevents many malicious attacks, threats, and vulnerabilities in your network.

Do you need a firewall?

You may think it is good to have a firewall, and you will be right! However, all Linux distributions come without a firewall. To be more correct, they come with inactive firewalls.

Because the Linux kernel has built-in firewalls, all Linux distros technically have a firewall, which is not configured and activated. The reason is that using a firewall requires some expertise.

However, do not worry! Your Linux-based system is still secure even without an active firewall. By default, most distributions, such as Ubuntu and Linux Mint, have no open ports.

Therefore, your computer cannot be accessed by intruders. Nevertheless, we recommend activating a firewall. It is better to be safe than sorry! It does not use many resources, but it adds an extra layer of security.

An inexperienced user installing samba, ssh, or apache can accidentally open some ports without knowing it. In this case, the firewall will still protect the system.

How to set up a firewall?

There are two ways to set up a firewall. Here, we are trying to describe them through some examples:

UFW

UFW is probably the most user-friendly firewall available in Linux. If you prefer to have a graphical interface, simply install GUFW.

How to use GUFW?

To use a GUFW firewall, you can follow these steps:

Install GUFW.
Open it.
In addition, please enable it.

Now, your firewall is active, and the default settings to deny incoming and allow outgoing connections are fine for most users. No one will be able to connect to your computer. At the same time, any application in your system could reach the outside world.

If you need to open some ports to connect to your computer from outside, go to the rules tab and open ports for the specific applications. For example, if you need to access your computer remotely through SSH, you should select the SSH option in the application list.

GUFW is a very simple and effective firewall application which can also be used from the terminal. To do that, you should follow these steps:

Open your terminal by pressing Ctrl + Alt + T.
Type in the below command to enable the UFW firewall:

$ sudo ufw enable

Enter the password.
Type in the below syntax to check its status:

$ sudo ufw status verbose

Now, you can see the rules deny incoming and allow outgoing connections.
If you need to open some ports, it is simple to run the following command:

$ sudo ufw allow ssh

In this way, you will allow SSH access to your computer.
If you check the status again, you can see SSH is allowed.

Iptables

Iptables is more advanced but probably a proper way to configure the Linux firewall. If you want some hardcore Linux experience, you can try to configure Iptables.

Iptables are not easy to understand. Therefore, you need to read a lot to understand how it works and how to configure it for your needs. Without going too deep, we will give some tips, which are important to know for beginners.

In this firewall, input is a chain used to control the system's behaviour regarding incoming connections and mostly deny them.

While the output is also a chain used for outgoing connections and to access internet websites. Therefore, you mostly keep it open.

There is also a forward chain. Unless you are doing some routing or something else on your system that requires forwarding, you will not even use this chain.

How to use Iptable?

To keep things simple, you might follow these steps:

First, you should type in the following syntax in your terminal to create the necessary chains:

$ sudo iptables –N TCP

Enter the password.
If you use Arch Linux, you can type in the following syntax to enable Iptables in the system:

$ sudo systemctl enable iptables.service

So, it starts with your system.
To make it executable, type in the following command:

$ chmod +x iptablea_ArchLinux.sh

And run it using the following syntax:

$ sudo ./iptables_ArchLinux.sh

It will implement all the rules required.

What are the best Linux firewalls in 2023?

Some of the best Linux firewalls in 2023 are as follows:

pfSense

pfSense is an open-source, free UTM firewall designed and distributed based on FreeBSD. It is used as a comprehensive, integrated threat management solution and centralized Internet and network bandwidth management.

This free and powerful software has been able to stand up to fierce competitors like Juniper and Cisco ASA and be included in the list of security and firewall contenders.

pfSense user-friendly environment and WEBGUI software, which manages through Shell and SSH, with a graphical environment that makes applying changes, settings, and reporting easy.

This software provides many security features in your network using software packages based on Linux and Opensource, such as Squid or Snort.

Key features

Some of the key features of pfSense are:

Real-time monitoring
Dynamic DNS
Including multiple DNS clients
Port/IP filtering and limiting network connections
Inbuilt load balancing
Network address translation
High availability
Supporting OpenVPN and IPsec
Preserves a full history of resource utilization to enable reporting

IPFire

IPFire is an open-source Linux-based distribution that works primarily as a router and firewall. It is an independent firewall system, providing the network administrator with a web-based management console for configuration and settings.

It turns PCs into routers so they can design routing systems and Internet gateways, and firewalls. IPFire is built on top of Netfilter to provide advanced security for enterprise networks.

It consists of a set of hooks in the Linux kernel and is used to block and manipulate packets. Therefore, it can act as a device that allows traffic to pass through the secure network and prevents insecure connections.

The simplicity and ease of management of IPFire are among the most important characteristics that make it more popular among users.

Key features

Some of the key features of IPFire are:

Packet inspection
Intrusion detection system
Offers a proxy server
Provides a virtual private network with OpenVPN and IPsec
WOL capabilities
Dynamic DNS
Offers a DHCP server

VyOS

Vyos is a completely open-source and free firewall written on Debian GNU Linux and can run on both virtual and physical platforms.

This software provides connection management services and supports VPN and network routing capabilities. It also supports Paravirtual drivers and integration packages in virtual platforms.

In addition, it supports advanced capabilities such as Dynamic Routing and Command Line interfaces.

Key features

Some of the key features of Vyos are:

Directing traffic
Tunnel interfaces
Static and Dynamic Routing
sFlow and NetFlow
Remote Syslog
Acting when an event occurs (Event Handling)
Web proxy and URL filtering (no HTTPS filtering)
Backup settings remotely
DHCPv6 and DHCP server and relay
VXLAN, static L2TPv3, SIT, IPIP, GRE, PPPoE
Network address translation

Untangle

Untangle is an open-source firewall which is quite similar to ClearOS and is based on Debian 8.4. Its Core network security functions are offered with free and paid plans to add additional functions and features, all managed through a web-based user interface.

The technical name of this dynamic firewall is NG, and it can be easily installed on any hardware or virtual machine in various formats.

Key features

Some of the key features of Untangle firewall are:

Web monitoring
Virus blocking
Advertisement blocking
Open VPN
Spam blocking
Firewall functions
Intrusion prevention

Smoothwall Express

Smoothwall Express is a free, open-source solution with a simple web interface and multiple applications to configure and manage the network connection. It can be turned off or restarted directly through the web interface.

Key features

Some of the key features of Smoothwall Express are:

Easy to use
Precise outgoing connection filtering
Listing malicious IP addresses to prevent the access
Port forwarding
Supports external connectivity through DHCP ethernet, PPPoA, PPPoE, and static Ethernet
Detecting intrusions systematically

OPNSense

OPNsense is an open-source, free, and secure firewall based on FreeBSD and uses two powerful IPFW and PF solutions. It supports both IPv6 and IPv4 and provides the best intrusion detection service.

This software is designed to manage the network bandwidth in the best way. In addition, it uses Suricata instead of Snort.

Key features

Some of the key features of OPENSense firewall are:

Supporting many plugins
Built-in monitoring and reporting tools
Detecting intrusions and preventing the system against them
VPN solutions

Endian Firewall Community (EFW)

EFW is a powerful security product based on Linux with easy installation, usually used for small networks.

Endian is a hardware device resistant to external attacks, including a firewall, antivirus, and anti-filter software. This hardware is considered an effective security management solution.

This flexible firewall protects your network against various attacks and threats.

Key features

Some of the key features of EFW are:

Provides real-time monitoring
Enhanced secure remote access
Improves web security
Improves email services security
Detecting intrusions and preventing the system against them

ClearOS

ClearOS is a Linux firewall based on CentOS, designed to replace Red Hat Enterprise Server or Windows Small Business Server completely.

It has several versions, including a free community version that provides various network services, a firewall, content filtering, and intrusion detection. You can easily install and configure this software.

Key features

Some of the key features of ClearOs are:

Managing bandwidth
Content and web proxy filtering
Detecting intrusions and preventing the system against them
Providing multiple security levels
File sharing management

The Bottom Line

Here, you learned about the best Linux firewalls in 2023 and their key features. In addition, we talked about the ways you can set them up. Please leave us your feedback and comments, and do not hesitate to ask any questions about these useful network security solutions. Good luck!

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Category: Linux Security