Re: pop3d keeps mailbox locked

[Sergey Poznyakoff]

Ken Olum <address@hidden> ha escrit:

> I switched to using mailutils for pop and imap.  Imap seems OK, but
> pop3d is keeping my mailbox locked even when it is not using it.

This behavior is entirely in accordance with the RFC 1939, which
mandates that

  "Once the POP3 server has determined through the use of any
   authentication command that the client should be given access to
   the appropriate maildrop, the POP3 server then acquires an
   exclusive-access lock on the maildrop, as necessary to prevent
   messages from being modified or removed before the session enters the
   UPDATE state.  If the lock is successfully acquired, the POP3 server
   responds with a positive status indicator.  The POP3 session now
   enters the TRANSACTION state"[1]

This state remains in effect until the UPDATE state is entered,
which happens

  "When the client issues the QUIT command from the TRANSACTION state,
   the POP3 session enters the UPDATE state."[2]

Then, finally

  "The POP3 server removes all messages marked as deleted from the
   maildrop and replies as to the status of this operation. [...]
   Whether the removal was successful or not, the server then releases
   any exclusive-access lock on the maildrop and closes the TCP
   connection."[2]
                             
In other words, a POP3 server must apply the lock right after the client
has been authentification and must release it only after the client has
issued the QUIT command.

Regards,
Sergey

[1] https://tools.ietf.org/html/rfc1939#section-4
[2] https://tools.ietf.org/html/rfc1939#section-6