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Introduction to Policies and Expressions
For many NetScaler features, policies control how the feature evaluates data,
which ultimately determines what the feature does with the data. A policy uses a
logical expression, also called a rule, to evaluate requests, responses, or other
data, and applies one or more actions determined by the outcome of the
evaluation. Or a policy can apply a profile, which defines a complex action.
Some NetScaler features use advanced policies, which provide greater
capabilities than do the older, classic, policies. If you migrated to a newer release
of the NetScaler software and have configured classic policies for features that
now use advanced policies, you might have to manually migrate policies to the
advanced-policy format.
In This Chapter
Advanced and Classic Policies
Advanced and Classic Expressions
About Migration from Classic to Advanced Policies and Expressions
Before You Proceed

Advanced and Classic Policies

Classic policies evaluate basic characteristics of traffic and other data. For
example, classic policies can identify whether an HTTP request or response
contains a particular type of header or URL.
Advanced policies can perform the same type of evaluations as classic policies. In
addition, advanced policies enable you to analyze more data (for example, the
body of an HTTP request) and to configure more operations in the policy rule (for
example, transforming data in the body of a request into an HTTP header).
In addition to assigning a policy an action or profile, you bind the policy to a
particular point in the processing associated with the NetScaler features. The bind
point is one factor that determines when the policy will be evaluated.