Windows 2000

Windows 2000 is still widely used. Many older machines have not been upgraded to Windows XP to save money, and Windows 2000 remains a serviceable operating system. Wireless configuration on Windows 2000 is significantly more complex than on Windows XP, in large part because it lacks solid integration between the selection of a wireless network and the corresponding security configuration.

Windows 2000 did not ship with 802.1X support from the start. It was initially added as a patch on top of Service Pack 3,[*] and was later integrated into Service Pack 4. Microsoft has not ported WPA functionality to Windows 2000, although a WPA client is available from the Wireless Security Corporation (http://www.wirelesssecuritycorp.com). Many observers feel that 802.1X support on Windows 2000 is not a priority for Microsoft, and its inclusion into recent service packs is an illustration of increased difficulty in persuading users to upgrade.

[*] See Microsoft knowledge base article 313664 for the patch.

Although 802.1X configuration has been integrated into the driver layer, Windows 2000 still depends on a card utility to configure which network the system will attach to. The separation can be particularly problematic for users who travel between an encrypted networks and unencrypted networks. Although using the card utility to switch networks is straightforward, it is usually necessary to manually enable or disable security. Windows 2000 may present network administrators with a difficult choice. If the software configuration tool bundles a third-party 802.1X stack, extra administration work must be done to separate the two.

Dynamic WEP Configuration

The Wireless Configuration Service on Windows 2000 only supports dynamic WEP for encryption. TKIP support is only possible by using a third-party supplicant. To configure dynamic WEP, set up the card's utility for use with manual WEP key. As far as the card utility is concerned, a manual WEP key is in use. Frames are dispatched by the driver to the card, to be encrypted by one of the keys stored in the card's key cache. The Wireless Configuration process, however, will push new keys into the card as required by the network's security policy.

The manual WEP key need not be configured anywhere else on the network. It must only be the correct length. For networks using 128-bit WEP, the key should be entered as 26 hexadecimal digits, such as 12345678901234567890123456. This dummy key is never used, since it is replaced by the dynamically derived key after a successful 802.1X authentication.

In my experience, the Wireless Configuration Service on Windows 2000 is not as reliable as the process on Windows XP. Several bugs have caused the service to fail after a successful authentication. Interestingly enough, the symptom of this type of failure is that the connection will be keyed succesfully, but traffic will be disrupted at the first reauthentication period. With no software running to process 802.1X frames, any attempted reauthentications or re-key operations will fail.

Introduction to Wireless Networking

Overview of 802.11 Networks

11 MAC Fundamentals

11 Framing in Detail

Wired Equivalent Privacy (WEP)

User Authentication with 802.1X

11i: Robust Security Networks, TKIP, and CCMP

Management Operations

Contention-Free Service with the PCF

Physical Layer Overview

The Frequency-Hopping (FH) PHY

The Direct Sequence PHYs: DSSS and HR/DSSS (802.11b)

11a and 802.11j: 5-GHz OFDM PHY

11g: The Extended-Rate PHY (ERP)

A Peek Ahead at 802.11n: MIMO-OFDM

11 Hardware

Using 802.11 on Windows

11 on the Macintosh

Using 802.11 on Linux

Using 802.11 Access Points

Logical Wireless Network Architecture

Security Architecture

Site Planning and Project Management

11 Network Analysis

11 Performance Tuning

Conclusions and Predictions

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802.11 Wireless Networks The Definitive Guide
802.11 Wireless Networks: The Definitive Guide, Second Edition
ISBN: 0596100523
EAN: 2147483647
Year: 2003
Pages: 179
Authors: Matthew Gast
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