The main difference between the rewrite feature and the responder feature is as follows:
Responder cannot be used for response or server-based expressions. Responder can be used only for the following scenarios depending on client parameters:
- Redirecting a http request to new Web sites or Web pages
- Responding with some custom response
- Dropping or resetting a connection at request level
In case of a responder policy, the NetScaler examines the request from the client, takes action according to the applicable policies, sends the response to the client, and closes the connection with the client.
In case of a rewrite policy, the NetScaler examines the request from the client or response from the server, takes action according to the applicable policies, and forwards the traffic to the client or the server.
In general, it is recommended to use responder if you want the NetScaler to reset or drop a connection based on a client or request-based parameter. Use responder to redirect traffic, or respond with custom messages. Use rewrite for manipulating data on HTTP requests and responses.