As more people gain access to the enterprise, the risk to network security increases, and WAN administrators must constantly strike a balance between connectivity and security. No security measure is foolproof, but there are steps you can take to minimize the risks.
As a rule, digital technologies are more secure than analog. Much to the chagrin of some federal agencies, the emergence of digital telecommunications technology has thwarted standard wire-tapping techniques. Recently, the FBI expressed frustration at its inability to tap ISDN circuits.
Given time, there is little doubt that the FBI, and others perhaps less honorable, will develop methods to trap digital data. Meanwhile, corporate data running over dig
ital links remains relatively secure.
ISDN has additional security available through ICLID (Incoming Caller IDentification). With ISDN, call setup messages contain the numbers of the calling and called parties. Network devices can be programmed to check the ICLID and reject connection attempts from unauthorized telephone numbers. LAN administrators must realize that ICLID information only indicates that the correct line is being used--it does not validate the user.
No matter what security measures are inherent in the technology you choose, continue to take more mundane defenses seriously. Passwords are a good first line of defense for keeping unauthorized remote users away from network services. However, password protection should be used only in combination with other security measures.
Authentication, based on Kerberos or internal codes created in WAN devices, is also valuable for WAN security.
Callbacks are another popular form of security for both analog and digital services. T
he user calls in, is validated, and is disconnected. The network then calls back the validated user. Besides providing security, callbacks can be a helpful tool for billing purposes.
There is also the possibility of unauthorized access through a telecommuter's workstation. The solutions here are much the same as those for the corporate environment. The workstation can be password-protected. Automatic log-ins should be prohibited.
Restricting physical access to the workstation at home is more difficult than in the office, but it can be done.
Stranger Danger
