Firewall & VPN



A firewall is your network's first line of defense. It is responsible for what traffic is allowed to come into your network - which, in a perfect world would be exactly ZERO.

But we don't live in a perfect world, and you may be hosting your school's, or company's website or email on a server inside of your network, so firewalls need to be flexible in their ability to protect and serve - keeping out the unwanted traffic while allowing in only what is specifically required.

While blocking unwanted inbound traffic to your network seems like a reasonable, and almost obvious thing to do, most people never even consider the idea that they should also be restricting the traffic that leaves their network.

Why would you want to block outbound traffic from your network? Well consider the following few examples:

  • BOT networks: Windows machines, once infected with a bot-net client will "phone home" to servers in other countries, check in, and await their commands.
  • Identity Theft: Windows machines infected with key logging or other similar malware will start collecting passwords by logging keystrokes or monitoring network traffic. Information collected is either emailed, or sent to servers in other countries.
  • SPAM Generators: Infected Windows machines, after contacting their SPAM network controlling server will start generating hundreds or even thousands of SPAM emails, using your workstations, and your Internet bandwidth to send SPAM - Often getting your network black listed, rendering you unable to send real email to your clients or constituents.

Each of the simple security vulnerability examples above may be mitigated by a combination of a firewall configured in a Default Deny mode for outbound traffic and a web filtering, and caching server.

Some examples of the firewall software that we install and support are listed below.





m0n0wall is a FreeBSD-based, open-source commercial-grade firewall solution complete with site-to-site IPsec VPN support, PPTP VPN support, traffic shaping, captive portal and an intuitive browser-based management interface. m0n0wall includes (FOR FREE) many of the features and functions that are normally only available in very expensive commercial firewall systems. And with m0n0wall there are no silly, arbitrary restrictions on the number of users, or number of connections you can support.

At Reverse Polarity, LLC, all of our clients' networks are protected by our custom-built, managed firewalls using m0n0wall as the underlying software. Call us and find out how we can help secure your network with one of our custom m0n0wall firewall solutions!

Reverse Polarity, LLC is proud to be a m0n0wall SPONSOR and an official m0n0wall MIRROR SITE!





pfSense is a free, open source customized distribution of FreeBSD tailored for use as a firewall and router. In addition to being a powerful, flexible firewalling and routing platform, it includes a long list of related features and a package system allowing further expandability without adding bloat and potential security vulnerabilities to the base distribution. pfSense is a popular project with more than 1 million downloads since its inception, and proven in countless installations ranging from small home networks protecting a PC and an Xbox to large corporations, universities and other organizations protecting thousands of network devices.

This project started in 2004 as a fork of the m0n0wall project, but focused towards full PC installations rather than the embedded hardware focus of m0n0wall. pfSense also offers an embedded image for Compact Flash based installations, however this platform is not its primary focus.





Untangle's multi-functional firewall software simplifies and consolidates the many network and security products that organizations need at the gateway to the Internet, making protection and filtering easy and affordable.

  • Affordable – Lowest total cost of ownership of any network gateway solution on the market today.
  • Comprehensive – Untangle handles web filtering, spam, network control, user management, bandwidth management.
  • Flexible – Add apps at any time to suit the changing needs of your business by simply dragging & dropping them in.
  • Proven – Untangle protects 1.7 million people in over 30,000 organizations worldwide.




Linux - IPTables Firewalls

Not looking for a web-based user-manageable firewall solution with all the gui bells and whistles? Let us configure and install a full-featured, custom built Linux firewall system using IPtables!