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OpenWrt Wireless Router
These pages detail my experiences with configuring and using
a Linksys WRT54GS running OpenWrt as a wireless router for a client
link on the Perth-based WAFreeNet.
Background
A friend who lives approx 400m away from my house wanted a wireless link to my
WAFreeNet
access point, and wanted to get the three computers in his house networked.
Rather than using a linux router, a wireless card (or AP in client mode), and a network switch,
I decided a WRT54GS running OpenWrt would provide a smaller and more efficient solution,
at a similar cost.
With linux on the WRT, it can provide DHCP, DNS, routing, firewall and VPN termination,
as well as providing sufficient switch ports to cater for each PC in the house.
Note that there never was any intention to use the 802.11g capabilities of the WRT
(as it would be connecting to a 802.11b access point),
and the two small dipole antennas supplied with the WRT would certainly not suffice
for a 400m wireless link.
The WRT54GS
The WRT54GS (versions 1.0 to 3.0)
is a Linksys wireless router with the following key features:
- 200MHz MIPS processor
- 32MB RAM
- 8MB flash memory
- 802.11b/g wireless access point
- built-in 4-port switch
- WAN/internet port
Note that the WRT54G has similar features, but only has 16MB RAM and 4MB flash memory.
Version 4 of the WRT54GS has the same features as listed above, but has half the memory
(ie, 16MB RAM and 4MB flash memory).
The version 5 WRT54G and WRT54GS cannot be flashed to OpenWrt (they have less memory,
and run a version of VxWorks, rather than linux).
OpenWrt Firmware
There are a number of alternative linux-based firmwares available for the WRT54GS,
but for various reasons, I decided to use
OpenWrt.
To quote from the OpenWrt website:
OpenWrt is a linux distribution for the Linksys WRT54G.
Instead of trying to cram every possible feature into one firmware,
OpenWrt provides only a minimal firmware with support for add-on packages.
For users this means the ability to custom tune features, removing unwanted packages
to make room for other packages and for developers this means being able to focus on
packages without having to test and release an entire firmware.
These pages were originally written in February 2005, but have been updated
with information relating to the white russian 0.9
build of OpenWrt.
The Wireless Network
I have a 180-degree slotted waveguide mounted on a mast on my roof, providing anyone within
range access to the WAFreeNet.
Some wireless stumbling indicated a 13dBi
double biquad antenna inside the friend's house
would provide a decent wireless signal to my waveguide.
The Network Environment
On the WAFreeNet, we generally use a /30 subnet for each client link, and allocate
an apropriately sized subnet for the client network (in this case, a /29 subnet).
The WRT would have to providing routing capabilities to route the /29 subnet over the /30 subnet,
provide DHCP and DNS to the client network, firewall traffic appropriately,
and also provide a VPN termination for all wireless traffic.
OpenWrt Configuration Details
I've provided more detailed configuration information, spread over several pages, with the
following major headings:
References
Here's some links I found useful while researching and configuring the WRT.
last updated 22 Oct 2013
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