User’s GuideWS_FTP ProBoth the client and the server have a protocol interpreter. The protocol interpreters receive commands or replies, send commands or replies, and govern the data connection. The server’s protocol interpreter listens for a connection from a client’s protocol interpreter.In an “active” transfer, the FTP server’s data transfer process initiates, or establishes, the data connection to the FTP client, setting up the parameters for data transfer and storage.In a “passive” transfer, the server’s data transfer process is placed in a passive state to listen for, rather than initiate, a connection to the data port. In this case, the FTP client initiates the data connection.FTP CommandsThe standard commands that an FTP client (such as WS_FTP Pro) issues to an FTP server a re listed here with a brief explanation that has been adapted from RFC 959. The command syntax is presented using BNF (Backus-Naur Form) notation where applicable.FTP commands may be in any order except that a “rename from” command must be followed by a “rename to” command and the REST (restart) command must be followed by the interrupted service command (e.g., STOR or RETR).ABOR (ABORT) ABOR <CRLF> This command tells the server to abort the previous FTP service command and any associated transfer of data.ACCT (ACCOUNT) ACCT <SP> <account-information> <CRLF> The argument field is a Telnet string identifying the user's account. The command is not necessarily related to the USER command, as some sites may require an account for login and others only for specific access, such as storing files.ALLO (ALLOCATE) ALLO <SP> <decimal-integer> [<SP> R <SP> <decimal-integer>] <CRLF> This command is required by some servers to reserve sufficient storage to accommodate the file to be transferred.
