DD-WRT is a linux based open source feature rich firmware which works with a wide variety of routers which are freely available.
For a comprehensive list of supported routers you can visit the Supported Devices Page.
The particular router which I have used for this test is a Netgear “WNR2000 v2” which was purchased from ebay for £15, flashing the new firmware was as simple as navigating to the upgrade firmware page on the router itself and pointing it to the .Bin file which I downloaded from DD-WRT’s website.
Adjust transmit power - boost the wireless transmitter up to a whopping 251mW. Note: Please keep in mind that FCC regulations restrict wireless transmit levels for devices like these. Turn up the power incrementally until you get the level of service you need; you do not want to get noticed by the Fed. You could also "drown out" other wireless signals that use the same channel. A lot depends on the antenna configuration used and other factors, so just be careful.
Afterburner - WRT54GS routers support SpeedBooster technology, and with wireless clients that support this feature, wireless performance can be increased significantly.
QoS - Use Quality of Service to prioritise types of network traffic. Let some applications have more bandwidth than others!
Dynamic DNS - Even without a static IP address from your service provider, you can access your router with a DNS name. dyndns.com provides a free service to associate a DNS name with your router (There are other DDNS providers, as well). If you need to get to your router from the outside world, dynamic DNS lets you have a consistent name that stays the same, even when its dynamic address changes (which it will, frequently).
VLANs! - establish virtual network segments using VLAN IDs and create more sophisticated network configurations.
WDS - Wireless Distribution System allows your router to talk to other routers as access points. This means you can extend the range of your network by letting routers talk with each other as bridges, resulting in wider network coverage.
Command shell - Add specific startup and/or firewall commands to be run when the router starts up to create even more customized configurations
Wake on Lan - Allowing you to turn on any number of computers on-site remotely.
Traffic Monitor - Monitor network traffic on all ports which can be logged and displayed graphically (see image below).
Web Hosting – You are also able to host a website on your router; complexity achievable would depend on how powerful the router you are using is.
Open VPN – Third part VPN software can be installed and configured to allow the use of public and private key pairs encrypting a VPN up to 4096bit.
Failover / Load balancing - Can also been configured (with abit of work) as a failover or load balancing device allowing you to combine the bandwidth of more than one internet connection which will also provide some level of redundancy. This means if one of your internet connections fails DD-WRT will continue using a single connection until the other one is back up.
Site forums provide a very reasonable level of support for this software and a large archive of walkthroughs detailing how to setup the more advanced features available thought the use of DD-WRT.
I have been using this firmware for 6 months now and found it to be very stable and provide a substantially more reliable wireless connection than the router provided to me by virgin media.
This firmware is now supplied from factory on a number of Buffalo’s higher end routers which speaks volumes for its credibility also the use of this firmware gives you access to features which would normally only be provided by routers which would be priced in the hundreds, which has cost me only £15.