A reference statement can be recognized by the suffix Ref. References provide a convenient way to reuse definitions, eliminating the need to repeatedly specify things such as host addresses and common services. Nearly all statements in the IP security configuration file can be referenced, and all action statements must be referenced. To be referenced, an IP security policy configuration statement must be given a user-defined name. Names of statements can be up to 32 characters. The following IP security policy configuration statements can be referenced, and therefore reused: