Monowall

Monowall is an open source firewall / NAT router that is completely free and available for download from http://m0n0.ch/wall/ the latest release is version 1.23 we have been using Monowall from version 1.0 on many different hardware platforms.

Here is what we like about the product it is completely stable we have a few of these in the fleet that have not been rebooted in over a year. In fact if you are only using it as a NAT router / Firewall once setup you should never have to reboot it unless you have to change hardware. We have run it on many different hardware platforms but for the most part run it on older Compaq Deskpro or HP Evo series desktops. The small form factors are the best you can screw ears into them and make them rack mounts pretty easily. All you really need to run Monowall is a PIII 733 or later and about 128mb ram. The only thing that seems to eat up the RAM and processor is when you are running VPN gates or doing traffic shaping then you want a better box a P4 with at least 256mb.

Another thing that is nice about this product is its ability to handle multiple incoming IP addresses many of the other open source firewalls cannot do this. Plus you can have multiple internal interfaces and multiple subnets so if your environment is larger you can have management / sales or other subnets that are separate. A lot of times we will use the Monowall as the outside or border router and than have something on the inside. In this instance Monowall works very well especially with the ability to have multiple internal interfaces.

You can also burn the Monowall config to a CD and boot from a CD this makes your hardware almost bullet proof. No one can hack your config. The one drawback to this is the fact that if you want to change anything you have to reburn another CD because once you reboot all of your changes are gone. You can put the config files on a floppy or usb device but we have not done this much for the most part we run our setups on a small hard drive 4.3 or less. These drives are almost free so you can make a couple of clones so if the drive failes you just put a new one in and in about 2 minutes you are back up and running.

Last but about the most important fact is Monowall is totally free so for about 300 dollars in hardware you could have a piece of equipment that will rival others costing thousands.