After enabling the rewrite feature, you need to configure one or more actions unless a built-in rewrite action is sufficient. All of the built-in actions have names beginning with the string ns_cvpn, followed by a string of letters and underscore characters. Built-in actions perform useful and complex tasks such as decoding parts of a clientless VPN request or response or modifying JavaScript or XML data. The built-in actions can be viewed, enabled, and disabled, but cannot be modified or deleted.
Target expressions in actions for TCP rewrite must begin with one of the following expression prefixes:
CLIENT.TCP.PAYLOAD. For rewriting TCP payloads in client requests. For example, CLIENT.TCP.PAYLOAD(10000).AFTER_STR("string1").
SERVER.TCP.PAYLOAD. For rewriting TCP payloads in server responses. For example, SERVER.TCP.PAYLOAD(1000).B64DECODE.BETWEEN("string1","string2").
You can use all types of existing string manipulation functions with these prefixes to identify the strings that you want to rewrite. To configure a rewrite action, you assign it a name, specify an action type, and add one or more arguments specifying