Best Open Source Firewall Solutions

By on August 22nd, 2016

Security is the most primary feature of any system. Any system is susceptible to denial of service, cracking, intrusion, snooping (intercepting the data of another user), or viruses/worms/Trojan horses. To protect the system from such attacking we use a secure box.

One of the steps to prevent such activities is using a firewall. A firewall is network security system, which protects the internal and external networks. The firewall works under a set of security rules, which allows you to control the flow incoming and outgoing traffic. The firewall rules explain the allowed connections, ports, and zones through which the connection is established.


1) pfSense

The pfSense project is a powerful open source firewall and routing platform based on FreeBSD. FreeBSD is an OS which is featured mainly on speed and stability. All the configuration settings are done through a web interface. The pfSense is powerful tool which provides maximum features with potential security vulnerabilities to the base distribution.

Firewall features include:

1) Stateful firewall.

2) Filtering by source and destination IP, IP protocol, source and destination port for TCP and UDP traffic.

3) Network Address Translation.

4) Filtering by source/destination IP address, protocol, OS/network fingerprinting.

5) Highly flexible policy routing possible by selecting gateway on a per-rule basis (for load balancing, fail over, multiple WAN, etc.)

6) Aliases allow grouping and naming of IPs, networks and ports.

7) Per-rule configurable logging and per-rule limiters (IP addresses, connections, states, new connections, state types), Layer 7 protocol inspection, policy filtering (or packet marking), TCP flag state filtering, scheduling, gateway.

8) Packet scrubbing.

9) Layer 2/bridging capable – can bridge interfaces and filter traffic between them, even allowing for an IP-less firewall.

10) State table “up to several hundred thousand” states (1 KB RAM per state approx).

11) State table algorithms customizable including low latency and low-dropout.


2) ClearOS

ClearOs is used to change any standard PC into a dedicated firewall and Internet server/gateway. ClearOS are mostly used for small business home offices, and networked homes. ClearOS is a CentOS based tool which has powerful tools that enhances the user to easily navigate to the administration pages. The administration pages are similar to the IPCOP and Smoothwall.


1) Firewall, Networking and Security.

Provides several levels of security.

At the network level, the firewall restricts access to your systems and provides advanced features, including DMZ, 1-to-1 NAT and Port Forwarding.

At the protocol level, the Peer-to-Peer detection system lets you manage peer-to-peer file sharing usage-at the application level, the Intrusion Detection and Intrusion.

Prevention systems provide another layer of defense against threats to your network.

2)Virtual Private Networking.

3) Web Proxy and Content Filtering.

4) E-mail, including Webmail.

5) Groupware.

6) Database and Web Server.


3) Untangle

Untangle’s Firewall filtering is based on traffic on IP address, protocol, ports, and allows administrators to assign which systems and services (http, ftp, etc.) are publicly available, create a DMZ and perform NAT (with Router), and run as a transparent bridge to complement existing hardware. Untangle has more features other than considering it as a firewall. In fact, it is a Linux distribution that has various softwares developed by other developers. Software includes a Web Filter, Spam Blocker, Spyware Blocker, Virus Blocker, Phish Blocker, Intrusion Prevention, Attack Blocker, OpenVPN, Router, Untangle Reports, and Untangle Platform.


1) Blocks sessions based on simple rules.

2) Rules can be based on a variety of attributes.

3) Custom logging, blocking or passing rules can be created by:



source address

destination address

source port

destination port


4) IPFire

IPFire is a Linux distribution system which has a different style of managing a complex firewall engine for administrators. It is maintained via an intuitive web interface. The distribution provides selected server daemons and can easily be expanded to a SOHO server. IPFire is used in an high performance networks and good with embedded hardware. It is designed to for tight security and protects itself from attacks from the network.


1)Stateful Packet Inspection (SPI) firewall, which is built on top of netfilter (the Linux packet filtering framework).

2) Proxy server with content filter and caching functionality for updates (i.e. Microsoft Windows updates and anti-virus).

3) Intrusion detection system (Snort) with intrusion prevention guardian.

4) VPN via IPsec and OpenVPN.

5) DHCP server.

6) Caching name server.

7) Time server.

8) Wake-on-LAN (WOL).

9) Dynamic DNS.

10) Quality of Service.

11) Outgoing firewall.

12) System monitoring and log analysis.

13) Custom package manager called Pakfire and the system can be expanded with various add-ons.


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One Response to “Best Open Source Firewall Solutions”

  1. Scott Noakes says:


    great article, thanks for posting. It might also be worth checking out Linewize, we’ve built an open source cloud managed layer 7 firewall specifically for education but works just as well elsewhere. Linewize provides complete visibility over internet use on a per user, device and application basis through our subscription services, all the firewall and filtering goodness is free for anyone to use. If you’re keen to have a look the install instructions are here Keen to know what you think.

    Cheers Scott.

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