7. Hacking the software

Linxsys routers run Linux from firmware. Linksys supplies source code on its site.

There are several replacements for the WRT54G firmware. All add certain commn features such as (a) the capability to ssh into the Linux running on the box, (b) European WiFi channels, and (c) VPN service.

Wifi-Box

Supports SNMP/mrtg. Said to have a good interface, convenient for home use.

SveaSoft

Intended for Wireless ISPs, lots of stuff for routing and repeater operation. Open source, but you can buy support and private-release subscriptions.

OpenWRT

Workbench for people who want to experiment with their own customizations. Provides a framework and a set of modular packages supporting particular features.

HyperWRT

Starts from the Linksys 3.01.3 firmware and adds a handful of features. Might be useful for those comfortable with the Linksys interface.

http://www.batbox.org/wrt54g-linux.html

Another hacker's workbench, this one runs from RAMdisk so you don't have to reflash the box. Thus there's no chance of trashing your router. The disadvantage is that it has to be reloaded each time after you power-cycle.

Any of these can be installed using the firmware upgrade procedures.

Firmware for other Linksys hardware (notably the WAP54G) can be found here and here.

For a look at the techniques used to develop these firmware alternatives, there's an interesting site on hacking the Wrt54g by Seattle wireless.net.