Authentication

Do you know if the user logged in is really that person? It is an all too
common practice for people to use other people’s accounts to authenticate
themselves to the server. In most wireless networks, businesses
often configure one account, “Wireless User,” and that account can be
used by several different devices. The problem is that a hacker (with his
own wireless device) could easily log onto to this general account and
gain access to your network.
To prevent an unauthorized user from authenticating himself into
your network, you can set your router to permit only connections from
authorized wireless network cards. Each wireless network card has a
Media Access Control (MAC) address that uniquely identifies it. You can
tell your router only to authenticate those wireless users with a network
card that is pre-authenticated to use your network. This protects you against users who are trying to gain access to your system by roaming
around the perimeter of your building looking for good reception to log
onto your local area network.