In this chapter you were introduced to the operations and deployment of a RADIUS server to be used with the 802.1x protocol for wireless user authentication. The server must be supplemented by a user database, so we studied the implementation of LDAP in some detail. Note that an additional benefit of deploying LDAP together with LDAP-based user accounts on mobile wireless clients can significantly alleviate the security consequences of physical wireless device theft. Finally, NoCat is described as an alternative and somewhat simpler to set up and administer user authentication solution for wireless networks. Because user authentication does not address data confidentiality and not everyone might be satisfied with the 802.11i standard or successfully deploy it across the available infrastructure, the next chapter is devoted to deploying affordable wireless VPNs and building custom VPN concentrators.