Linux Desktop Hacks

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Chapter 9, Administration and Automation

#81 Build a Custom Firewall Computer

HACK

• If you have any computers that need to be accessed publicly, you need

another network card for these. This card is referred to as the ORANGE

interface and also is known as the snazzily titled De-Militarized Zone

(DMZ), because it exists in a sort of no man’s land between the public

Internet and your private network.

You should install the cards you need in the computer, download the Smooth-

Wall ISO from http://www.smoothwall.org, and then burn the ISO to CD.

The next step is to boot from the CD and install the SmoothWall software.

If you cannot boot from the CD, try using the Smart Boot Manager dis-

cussed in “Give Your Computer the Boot”

[Hack #1]. If this does not work, you

can create a series of boot floppies from the files found in the images direc-

tory on the SmoothWall CD. There you’ll find two boot floppy images

called bootdiskone-x.x.img and bootdisktwo-x.x.img. Use

dd to create the

floppies (unmounting and changing the floppy between images, of course):

foo@bar:~$ dd if=bootdiskone-x.x.img of=/dev/fd0 bs=1024 conv=sync ; sync

foo@bar:~$ dd if=bootdisktwo-x.x.img of=/dev/fd0 bs=1024 conv=sync ; sync

If you need to create the floppies on a Windows system, you can use the

rawrite program (http://uranus.it.swin.edu.au/~jn/linux/rawwrite.htm) to cre-

ate the disks.

Installing SmoothWall is a fairly simple ...