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Build This Cheap But Effective Firewall

Fight the bad guys without busting your budget. Here's all you'll need to create a low-cost, super-secure firewall using Linux-based freeware and an old PC.

How to Install SmoothWall Express

  1. Insert the SmoothWall Express CD into the CD-ROM drive of a Windows PC (Internet Explorer, version 5.5 or later, is recommended). The Autorun procedure lets you read the license; view/print the Installation and Administrator's Guide in Adobe Acrobat format; create boot floppy disks; browse the CD; and download Adobe Acrobat Reader.

  2. View the Installation and Administrator's Guides using the Acrobat Reader. Print or save copies to the hard disk of your Windows PC, so you can refer to them during the installation.

  3. Make sure the PC can boot from the CD-ROM drive. Most PCs from P166 onwards can be set to do this in their BIOS. If your PC is already set to boot from CD-ROM, skip ahead to step 5.

  4. If the PC cannot boot from CD, you will need to create two boot floppies, which you'll use to start the installation process. Do this with either the Autorun procedure or by running the RawWriteWin.

  5. Start with a powered-down PC. Load the SmoothWall Express CD into the CD-ROM drive of the target PC. Then power up the PC; it will boot from the CD.

  6. You will be greeted by a prompt informing you that the installation of SmoothWall Express is about to start. Press the Enter key to proceed. Follow the installation process.

  7. You will be prompted to choose the language you wish to use for the installation. English is the default.

  8. Select the install software from CD-ROM options.

  9. Confirm that the PC's hard disk is to be re-formatted. All existing data on the disk will be lost, so if you need to keep any data, cancel the installation of SmoothWall Express now.

  10. Once the PC's hard disk has been prepared, the SmoothWall Express software will be copied across from the CD.

  11. The software will probe the PC to determine what hardware is installed. It looks first for a Network Interface Card (NIC or LAN card), which is later used to connect SmoothWall Express to the local (protected) network. Virtually all PCI bus cards will be automatically recognized and configured, as will some (but not all) ISA bus cards. The Smoothwall Express Installation and Configuration Guide contains additional information on how to configure cards which cannot be automatically detected.

  12. Supply a TCP/IP address for this card. Most small networks can safely use the default settings. Internal private addresses, such as this, are never exposed to the Internet.

  13. A message is then displaying saying that the SmoothWall Express software has been successfully installed. Remove all CDs or floppy disks, and press the OK button to run Setup. The Setup menu should appear looking pretty much like this:

  14. The Setup Program completes the basic configuration of SmoothWall Express. It lets you configure your keyboard layout, host name, DHCP server, system passwords, and any proxy server settings you need. It will then probe for and configure ISDN cards, USB hardware, and NICs. If the machine is connected to the Internet via either an Ethernet router or cable modem, you will need to configure a second NIC and select the GREEN + RED network configuration. If your Internet connection is via ISDN, USB ADSL, or a dial-up modem, then use the default GREEN (RED is modem/ISDN) network configuration.

  15. Most ISPs don't use Proxy Servers, but if yours does, you will now enter its Hostname and IP port.

  16. If an ADSL modem is to be used, you need to select the make/model and VCI/VPI parameters configured in the Setup program. Likewise, for an ISDN connection, the ISDN card must be either automatically probed or manually selected from the list. USB ISDN adapters cannot be identified by probing, so they must be selected and configured by hande. You'll also need to configure ISDN parameters such as the protocol and local phone number, too.

  17. If the computer has an Ethernet connection to the Internet, you should either specify the IP address of the RED (Internet) interface as a static, public IP address or configure it to request a dynamic (DHCP) address from the router to which it is attached.

  18. Setup finishes by rebooting the PC. Before confirming the reboot with the OK button, ensure that all the network cables are plugged in and that your modem or ISDN card (if present) is connected. After the reboot, when SmoothWall Express has been initialized and is ready for use, you should be presented with a simple Unix/Linux-style Login screen.

Configuration and Testing

Once again, SmoothWall Express includes an Administrator Guide, which you'll find either on SmoothWall Express' CD or from SmoothWall's Documentation Web page. It can help you through configuration questions and provide useful insight into how SmoothWall can be used with a variety of networks. It can also show you how to create well-protected network architectures for clients.

Finally, don't forget to test your configurations. To test your hardware firewall security, you can use third-party test software. Or you can search the Internet for free online-based firewall testing services, such as the one from AuditMyPC.com. Either way, firewall testing is vital. It ensures that a system is always configured for optimal protection. Also, remember to monitor the firewall after it's been installed (or train the user how to do this), and be sure to download updates as they become available.

There's always another hacker out there waiting for you to let down your guard. With a well-configured firewall, you can stay a step ahead of the bad guys.

ANDY MCDONOUGH is a New Jersey-based musician, composer, voice actor, engineer, educator, and freelance writer.

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