Network Authentication CHAPTER 8 113 AUTHENTICATION SYSTEMS Authentication systems are used to provide user authentication in a wide variety of applications from local domain service to online banking systems. This sec- tion covers Remote Authentication Dial In User Service (RADIUS), Kerberos, and LDAP authentication services and TACACS as well as authentication pro- tocols including PAP, CHAP, and 802.1x. Remote access policies and authentication Remote users may connect to a network through dial-in services using an ana- log line and a modem by dialing in to an organization's modem pool con- nected to a dial-in server, or through a VPN client software configured on their laptops or remote desktops to connect to the corporate VPN server. Even wire- less clients connecting through the WAPs can be defined as remote users and restrictions can be applied on them. A remote access policy defines the con- ditions and remote access permissions, and creates a profile for every remote connection made to the corporate network. Fast Facts