4.5.1. The Finger protocol

Finger is a request/response based User Information Protocol using port TCP/79. The client opens a connection to the remote machine to initiate a request. The client sends a one line query based on the Finger query specification and waits for the answer. A remote user information program (RUIP) processes the query, returns the result and closes the connection. The response is a series of lines consisting of printable ASCII closed carriage return-line feed (CRLF, ASCII13, ASCII10). After receiving the answer the client closes the connection as well.

The following queries can be used:

  • <CRLF> This is a simple query listing all users logged in to the remote machine.

  • USERNAME<CRLF> A query to request all available information about the user USERNAME.

  • USERNAME@HOST1<CRLF> Request the RUIP to forward the query to HOST1. The response to this query is all information about the user USERNAME available at the remote computer HOST1.

  • USERNAME@HOST1@HOST2<CRLF> Request HOST1 to forward the query to HOST2. The response to this query is all information about the user USERNAME available at the remote computer HOST2.