Using Kerberos, RADIUS, and LDAP for WLAN Authentication
While wireless networking applications benefit from location
independence and freedom of mobility, they all have the same security challenge—
authentication. When considering a security implementation, authentication is a
key component of any security solution. Mutual authentication, where both the
client and the server must authenticate with each other, is used to ensure that
only authorized users are allowed on the network. Kerberos, Remote
Authentication Dial-In User Service (RADIUS), and LDAP are popular and useful
authentication solutions that meet this security challenge in WLANs.
Kerberos is designed to enable two parties to exchange private
information across an otherwise insecure network. Kerberos provides mutual
authentication between a client and a server, as well as between servers, before
a network connection can be opened. It uses a technique that involves a shared
secret, which works much like a password. This happens by assigning a unique
key, called a ticket, to each user who logs on to the network. The ticket is
then embedded in messages to identify the sender of the message.
RADIUS servers are robust, scalable servers that provide
authentication, authorization, and accounting (AAA) functions and advanced
policy and custom configuration management
to control user access to wired and wireless networks. Radius and LDAP are often
used together in WLAN applications.
The Lightweight Directory Access Protocol (LDAP) is an extensible,
vendor-independent network protocol standard, an authentication system, and a
directory service that is based on the X.500 Directory Services model. LDAP is
an information repository as well as a protocol for querying and manipulating
the data in an LDAP directory. LDAP is one of the most widely used
authentication directories in modern networks. LDAP is based on the standards
contained within the X.500 standard but is much simpler and supports TCP/IP,
which is necessary for any type of Internet access. Many of today's WLAN
security devices, such as Enterprise Wireless Gate-ways (EWGs), have native LDAP
client support.