Wireless Networks concepts in Windows Server infrastructures


In this article I will start presenting the Wireless concepts and technologies available with Windows Server 2008. In our days, wireless connectivity has become a critical component and most enterprises are implementing this technology all around the world. Wireless networks can be relatively easily implemented within large enterprises because these connections go beyond the workload and limitations of physical connections. Most home networks have at least one wireless AP or router that is used to connect directly to the Internet. In most situations tablets, mobile phones and laptops are using a wireless connection to connect to other devices. Though wireless connections offer flexibility they have some flaws in terms of privacy security. These connections are susceptible to attacks and information theft. Older encryption mechanisms like WPA (Wi-Fi Protected Access) or Wired Equivalent Privacy (WEP) were easily cracked by a skilled hacker because they didn’t used strong algorithms. We will discover what are today’s wireless standards and what encryption algorithms are used in wireless technology.
The common Wireless Standards that are widely used today are the following:
802.11a – one of the first wireless standard ever used. It was not as popular as 802.11b because it used the 5Ghz frequency spectrum and it offered a low speed.
802.11b – this is the most common wireless standard that is used in our days. It is one of the original standards created for wireless technologies. 802.11b offers a bandwidth up to 11 Mbps and is using the 2.4GHz frequency spectrum. Newer wireless standards are compatible with this technology this is why devices using this standard can connect to almost all Wireless connections. This standard was adopted because it was cheap and the signal penetration was pretty good. The main downside of this technology is the low speed.
802.11g – is an upgraded wireless technology that offers a bandwidth up to 54 Mbps and uses the 2.4Ghz frequency spectrum. Note that speeds mentioned here are in Mb and only the bandwidth is mentioned (not the actual data transfer). This standard is backward compatible with 802.11b so devices can easily connect. It offers an increased speed but, the implementation cost is higher than in 802.11b technology. Note that devices using this standard can interfere with home appliances.
802.11n – a newer implementation of the 802.11g standard. It offers an increased bandwidth (up to 250 Mbps) and is compatible with older wireless technologies.
You may encounter other wireless standards used by different vendors that are proprietary or are not so widely used. Even thought these technologies may offer an increased speed, they are often not compatible with other devices and are not used within large networks.

Wireless networks can be configured in two ways:
Ad-hoc – wireless communication channels are established between devices by using their wireless network cards. This is not a method widely used because it has limitations in terms of speed, range, number of interconnected devices and so on. Ad-hoc connections can be easily configured with Windows computers.
Infrastructure – is the operating mode widely used in wireless networks. Enterprises and even home networks are using wireless AP to interconnect devices. The Access Point acts as the central piece in the communication process. The AP will receive traffic from one device and will forward it to the desired destination.
To authenticate and encrypt traffic in wireless networks, protection mechanisms were developed over time to fulfill this need. If needed, you can configure your AP (Access Point) to use no security when clients are connecting to the network. This means that authentication is not needed and the traffic will not be encrypted. This method is not recommended since wireless traffic can be intercepted and read in clear text. Whenever possible try to avoid using this method.
WEP or Wired Equivalent Privacy – is one of the first security measurements implemented in wireless networks. This mechanism is using either a 64 or 128 bit encryption key. This encryption algorithm proved to have weak protection against cracking. By using dedicated software a hacker could easily discover the key used to connect to the wireless network. For this reason, this encryption algorithm is not often used. All wireless device support this protection mechanism.
Wi-Fi Protected Access (WPA) – this is a newer encryption mechanism developed to surpass his predecessor in terms of network protections. WPA offers both authentication and encryption methods and was designed to be easily adopted by network devices. Windows computers have two WPA methods available:
  1. WPA-PSK (preshared key) – this WPA extension uses a static key to allow network computers to connect to the wireless infrastructure. Just like WEP, this WPA version is susceptible to network attacks because the key can be discovered using dictionary or brute force attacks. Most home wireless connections use this kind of security measurement because it is easily implemented and configured .
  2. WPA-EAP (Extensible Authentication Protocol) – is a protection mechanism that uses Remote Authentication Dial In User Service (RADIUS) servers to provide authentication for users. This means that before a user is able to surface the network, it’s connection request is sent to the RADIUS server for authentication. The Windows RADIUS server can be configured by adding the Network Policy Server (NPS) role. We will configure such server in a future article. NPS allows administrators to configure Active Directory authentication. This means that a preshared key is not needed but, instead computers are authenticated directly using AD. RADIUS server provides a greater method of protecting your network against external attacks. Unlike other encryption and authentication methods, WPA-EAP is much harder to crack.
WPA2 – is a new protection mechanism that was developed to provide an even grater encryption mechanism than WPA. It uses a newer version of the encryption algorithm but, it is not supported by all devices. You would often need to upgrade the firmware of an AP to support this newer WPA version. WPA2 is supported by all Windows clients. For Windows XP you would need to install the latest updates. Just like WPA, this protection mechanism can be implemented in two ways: WPA2-PSK and WPA2-EAP
That’s it for this article, hope you will enjoy it. This was a short introduction of Wireless networks available with Windows OS. For additional information check out one of previous articles about Wireless concepts. Enjoy your day and stay tuned for the following articles from IT training day.
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