POP Protocol commands

Command Syntax Description 
USER user username  Provides username to the POP3 server. Must be followed by a PASS command. 
PASS pass password  Provides a password to the POP3 server. Must follw a USER command. 
STAT stat Returns the number of messages and total size of mailbox. 
LIST list
list mesg_number Lists message number and size of each message. If a message number is specified, returns the size of the specified message. 
LAST last Returns the message number of the last message not marked as read or deleted. 
RETR retr mesg_number Returns the full text of the specified message, and marks that message as read. 
TOP top mesg_number lines Returns the specified number of lines from the specified mesasge number. 
DELE dele mesg_number Marks the specified message for deletion. 
RSET rset Resets any messages which have been marked as read or deleted to the standard unread state. 
NOOP noop Returns a simple acknowledgement, without performing any function. 
APOP apop username encrypted_key Allows for a secure method of POP3 authentication, in which a cleartext password does not have to be sent. Instead, the client creates an MD5 encrypted string from the password, process id, and timestamp, and sends it to the POP3 server. 
QUIT quit Ends the POP3 session