How To:LAN Firewall with IPTables (I)

June 19, 2007

Hi again!

When you want a homemade firewall, we have some options, buying a “physic” firewall, installing a software in each one computer of the LAN or mount our IPTables firewall using an old computer. The first option its very expensive for home users, the second could be a valid option, but if we have different operating systems installed in our LAN, we need to manage different firewall software depending on the OS, or install the same in all the computers of our LAN. a lot of work to do!!. The last its a very very boring option 😛 . The option of using an old computer, probably are the best and the cheapest we can use to build our homemade firewall.


This is all we need to build the firewall :

  • Old computer (Or new one if you prefer it..)
  • Two ethernet cards
  • A 10/100 or similar Switch
  • Linux (*NIX) distro installed

The scheme of the network situation its something like this pic:

I have always used Debian or Gentoo distro, but all Linux distros works to do this. Only one more thing, you must have installed the necessary Kernel modules to use IPTables (later called NetFilter).

In the next post i’ll comment on the necessary Kernel modules, commands and an example script to do the Firewall 🙂

See you!



  1. El Firewall más fiable es el del WindowsXP. Lo pone en la caja.

  2. Sin duda … xD

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