Pop3d listens for TCP requests on port 110. Once connected it expects single line commands terminated by a <CR-LF>.
Pop3d currently supports the following POP3 commands; the commands are case independent. In addition, the server supports one extension command, HOST, which allows access to BSMTP formatted maildrops in the directory /private/spool/pop.
The syntax for the HOST command is: HOST <hostname>
Example: HOST fennario.ucdavis.edu
this will open the file at /private/spool/pop/fennario.ucdavis.edu
Command Description
USER specify user for maildrop access
PASS specify password for maildrop access
STAT give message count and size of maildrop
LIST list size of individual messages
RETR retrieve a message
DELE delete a message
NOOP do nothing, return a positive response
LAST give highest message number accessed
RSET unmark messages marked for deletion
TOP retrieve part of a message
QUIT terminate session
The remaining optional command specified in RFC1225 (RPOP) is not implemented.