Internet Direct (Indy) Version 9.0.1 Beta
TIdPOP3Server.OnCommandAPOP
Event handler signalled perform alternate authentication for the client thread.

property OnCommandAPOP: TIdPOP3APOPCommandEvent;
Description
OnCommandAPOP is a TIdPOP3APOPCommandEvent property that represents the event handler signalled when a threaded POP3 client connection performs the APOP command verb. OnCommandAPOP is used to implement an alternate method of authentication which does not involve sending a password as clear text over the network.

When the client thread is executing using the OnExecute event handler, the command with the mailbox identifier and digest arguments are read from the connection. The client thread and command arguments are provided to the TIdPOP3APOPCommandEvent event handler for execution of the code that implements the specific server functionality.

AMailboxID is the POP3 account name (or mailbox) accessed by the client connection.

ADigest is the 16-octet hexadecimal MD5 Message Digest calculated by applying the MD5 algorithm specified in RFC 1321 to a string consisting of the timestamp (including angle-brackets) followed by the shared APOP secret for the client connection.

OnCommandAPOP must verify the digest provided. If the digest is correct, the POP3 server issues a positive response, and the POP3 session enters the POPStateTransaction state. Otherwise, a negative response is issued and the POP3 session remains in the POPStateName.

The POP3 server implementation must assign a procedure to the event hadler to allow responding to the event notification, or a POP3 protocol error response will be sent to the client connection.