In the first installment of this tutorial series, you discovered that WPA-Enterprise encryption is the way to go if you desire a bulletproof Wi-Fi network. You also found out a few ways you can go about setting up this encryption method for your small or home office network. This tutorial will continue by introducing you to the basics of an 802.1x RADIUS server environment and the steps to setting it all up. Youll soon be on the road to running your very own server for WPA-Enterprise encryption.
Interworkings of an 802.1x RADIUS Server Setup
For the most part, 802.1x RADIUS servers are set up and work in a similar manner to one another. The RADIUS server software acts as the gateway to the network; users must pass it before theyre allowed access to the network and the Internet. It receives requests that originate from users and sends back messages to approve or deny users to connect to the wireless network. This request may contain, for example, a user name and password, which the RADIUS server checks against a user database (Active Directory, SQL database, MS Access, servers built-in database, etc.). The messages to and from the users and the RADIUS server go through a coordinator or middleman, called a network access server (NAS) or RADIUS client, such as your wireless router or APs. Figure 1 (below) shows a simplistic example of these components and the process of authenticating a user onto a wireless network.
Another component you should be familiar with in this type of environment is a digital certificate. When you set up a RADIUS server, you install a digital certificate (a small file that serves as a computers ID) on the server. During the authentication process, the user computer validates whether the RADIUS server is trustworthy. The computer does this by running the digital certificate installed on the server through a Certificate Authority (CA) that vouches for the servers identity. A digital certificate is comparable to a signed letter stating a persons identity, a CA is similar to a public notary, and the CAs official verification of the computers identity being the equivalent as an affidavit.
For most small business and home deployments, using a third-party CA is not cost-effective. In these instances, the same digital certificate thats installed on the RADIUS server must also be installed on the user computers. For easier configuration of computers on larger networks, a certificate designed for WLAN authentication and signed by a trusted authority (such as Verisign) can be purchased. Instead of manually installing a self-signed certificate on all your computers, the computers would validate the servers identity using a real CA thats by default trusted by Windows.
Figure 1. The authentication standard represented in Figure 1 and explained in this section is that of Protected Extensible Authentication Protocol (PEAP).
Basic Steps of Setting Up a RADIUS Server
Before you dive headfirst into installing and configuring, you should review the overall steps to setting up your WPA-Enterprise network using an 802.1x RADIUS server:
Thats it in a nutshell; now well go step-by-step through the process.
Preparing your server PC
You need to choose which computer youre going to install the server software on, which well call the server pc. Its best to dedicate a computer solely for the purpose, however, if it isnt super-critical to have your wireless network up 24/7, you can get away with using the PC for day-to-day tasks in addition to hosting your authentication server. Remember, if the server PC is shut down, restarting, or crashes, users cant connect to your wireless network. Users already authenticated and connected should still be able to use the network when the server PC is down, but they can be kicked off after their session times out and needs to communicate with the server again.
The server PC will need to be hooked directly into the network via an Ethernet cable rather than wirelessly. In addition, the PC should have a static IP address as opposed to having an address assigned automatically to it by using DHCP. This is because youre going to be inputting the IP address of the server PC into your wireless router and/or access points (APs), thus it needs to remain the same. You can either assign a static IP address to your computer in Windows (on the TCP/IP Properties window of your network connection) or use a DHCP reservation feature on your router to ensure your server PC always receives the same IP address.
Stay tunedthe next installments will take you through the remaining steps to get a RADIUS server installed and WPA-Enterprise security running on your Wi-Fi network.
Eric Geier is the Founder and President of Sky-Nets, Ltd., a Wi-Fi hotspot network. He is also the author of many networking and computing books, including Home Networking All-in-One Desk Reference For Dummies (Wiley 2008) and 100 Things You Need to Know about Microsoft® Windows Vista (Que 2007).
This article was first published on WiFiPlanet.com.