802.1X Authentication Registry Hacks in XP

by Eric Geier [Published on 1 Feb. 2011 / Last Updated on 4 Dec. 2009]

Modifing the Pairwise Master Key (PMK) and Preauthentication settings for better roaming.

Though 802.1X can provide secure authentication for networks, it adds another step to the wireless connection process. This isn’t good for clients that must be able to roam around a building, going from one access point to another. However, you can fine-tune the Pairwise Master Key (PMK) and preauthentication settings via the Windows XP Registry to make roaming better:

Hive: HKEY_LOCAL_MACHINE
Key: \SOFTWARE\Microsoft\EAPOL\Parameters\General\Global

Name: PMKCacheMode
Value: 0 (disabled), 1 (enabled)
Turns PMK caching on and off.

Name: PMKCacheTTL
Value: 5-1440
Number of minutes to keep PMK entries cached, up to 1440 (24 hours).

Name: PMKCacheSize
Value: 1-255
Maximum number of PMK entries that can be cached.

Name: PreAuthMode
Value: 0 (disabled), 1 (enabled)
Whether or not the client should try preauthentication.

Name: PreAuthThrottle
Value: 1-16
Number of top preferred wireless access points that the client will try preauthentication with, based on the order of networks provided by the wireless adapter.

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