Just started using SmoothWall. All I have is a household with 2 students, each with their own XP home PC, and the associated risks of thir download and surfing activities, and my 2 work machines, running XP and Win98 SE respectively. 24/7 Internet access is via cable TV set top box from NTL.
I dug out an old Pentium P100, with 64 Mb ram (overkill!) and a 1 gig HDD, CDrom drive, a couple of old 3Com network cards, one of which had been registered with NTL on my original XP box. Value - less than £150.
Downloaded smoothwall 1.0 in advance from
and burnt a bootable CDrom with the smoothwall installation iso - free download.
Set the bios to boot from CD and setup the smoothwall to use the nic that was registered as the internet side or RED interface, and the other nic as the network side or GREEN interface. Use well known makes of NIC - see the documentation for the supported cards.
Add the user information and passwords, connect the machine to the network hub and the net access, and I have a working firewall, intrusion detection system and proxy server.
Set up the other machines to use this as a gateway and DHCP server Apart from a few tweaks to do with the rate of growth of log files, by changing configuration files to change logs daily, instead of weekly. The firewall has a built-in secure web server, so I can administer the firewall using SSH from any browser, even reboot it if necessary. I have unplugged the monitor and keyboard, and it runs almost silently in the corner of my bedroom.
The learning curve is not too bad once you have the right tools (WINSCP to view the firewall filesystem and edit files from a remote windows machine securely) and support from the smoothwall community forum postings on their website. You could also use it to set up a secure VPN to work on the network remotely.
Well within the $300 budget you have, and you don't need to be a Linux buff to use it, though you may become one <g>.