The security-related decisions you make, or fail to make, as administrator largely determines how secure or insecure your network is, how much functionality your network offers, and how easy your network is to use. However, you cannot make good decisions about security without first determining what your security goals are.

Until you determine what your security goals are, you cannot make effective use of any collection of security tools because you simply will not know what to check for and what restrictions to impose. For example, your goals will probably be very different from the goals of a product vendor. Vendors are trying to make configuration and operation of their products as simple as possible, which implies that the default configurations will often be as open (i.e., insecure) as possible. While this does make it easier to install new products, it also leaves access to those systems, and other systems through them, open to any user who wanders by.

Your goals will be largely determined by the following key tradeoffs:

1. services offered versus security provided -

Each service offered to users carries its own security risks. For some services the risk outweighs the benefit of the service and the administrator may choose to eliminate the service rather than try to secure it.

2. ease of use versus security -

The easiest system to use would allow access to any user and require no passwords; that is, there would be no security. Requiring passwords makes the system a little less convenient, but more secure. Requiring a device-generated one-time password makes the system even more difficult to use, but much more secure.

3. cost of security versus risk of loss -

There are many different costs to security: monetary (i.e., the cost of purchasing security hardware and software like firewalls and one-time password generators), performance (i.e., encryption and decryption take time), and ease of use (as mentioned above). There are also many levels of risk: loss of privacy (i.e., the reading of information by unauthorized individuals), loss of data (i.e., the corruption or erasure of information), and the loss of service (e.g., the filling of data storage space, usage of computational resources, and denial of network access). Each type of cost must be weighed against each type of loss.

Your goals should be communicated to all users, operations staff, and managers through a set of security rules, called a "security policy." We are using this term, rather than the narrower "computer security policy" since the scope includes all types of information technology and the information stored and manipulated by the technology.

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