The Wall Server Security WebStalker Pro Internet Security Authentication Firewalls do their authentication using IP addresses which are assigned to each server, client, and network device and can be spoofed. So if you want to give certain users access over the Internet to sensitive internal files and data, you'll want to make sure to authenticate the actual user.
Authentication simply describes the numerous methods that positively identify a user.
Passwords are the most common method of authentication used today, but users are notorious for making poor password choices that can be guessed by an experienced hacker. Many of these products use a challenge-response scheme. When the user attempts to connect, an authentication server on the network issues a challenge, which the user keys into the token device. The device displays the appropriate response, which the remote user then sends to the server. Less expensive software versions of tokens are available.