Finally, many pages into the chapter, we get to the part about how to solve the problem. It has taken this long because the concepts we have discussed so far are barely touched on in the vast majority of security literature, which often does not even mention these issues.
One of the most important techniques for mitigating security dependencies today involves isolating computers that do not need to communicate so that they cannot do so. Microsoft calls this Server and Domain Isolation. To build a strategy to do so is best done in a step-wise process:
Define a classification scheme.
Model your network.
Analyze your network model relative to the classification scheme.
Revise the classification scheme as needed and reanalyze.