Each device that links to a network has the potential to cause a security problem or to be infected by viruses. Network administrators have to clearly define network access policies. The devices on the network and the users who use the devices must comply with the network access policies. When setting up the online computer lab for a class, the network administrator must decide who can access what devices and use which applications, and make sure that only authorized users can access the dedicated devices. Once a user successfully logs on to a device, further access policies will be enforced to specify which servers the user can communicate with, which protocols are allowed in a communication, which network can be accessed, and which network services can be used by the user. A wrongly configured network can cause security holes. Later, we will take a closer look on network access policies.
