Chapter 12 Configuring Classic Policies and Expressions 209
5. In the Priority field, set the priority.
6. If you are binding policy to a Content Switching virtual server, in the
Target field select a load balancing virtual server to which traffic that
matches the policy is sent.
7. Click OK.
Creating Named Classic Expressions
Named classic expressions are expressions that are given a name and can be used
in any classic policy. Some named expressions are built-in, and a subset of these
are read-only. You can also configure new named classic expressions.
Built-in named expressions fit into one of four categories: General, Anti-Virus,
Personal Firewall, and Internet Security. General named expressions have a wide
variety of uses, including the following:
• Allowing a value of TRUE or FALSE to always be returned for all traffic.
The general named expressions ns_true and ns_false provide these
options.
• Identifying data of a particular type (for example, .htm, .doc, or .gif files).
• Determining the presence of caching headers.
• Determining whether a round trip between a client and the NetScaler is
slow (over 80 milliseconds).
Anti-Virus, Personal Firewall, and Internet Security named expressions test
clients for the presence of a particular program and version and are used primarily
to create Access Gateway policies.
For descriptions of the default named expressions, see “Classic Expressions,” on
page 224.
Note: You cannot modify or delete built-in named expressions.
To create a named classic expression using the configuration utility
1. In the navigation pane, expand AppExpert, expand Expressions, and then
click Classic Expressions.
2. In the details pane, click Add.
Note that some of the built-in expressions in the Expressions list are read
only.