NAME

       mpopd - A minimal POP3 server

SYNOPSIS

       mpopd [option...]

DESCRIPTION

       Mpopd is a minimal POP3 server that delivers mails from a local mailbox in maildir format. It can be used
       by  end  users as a way to handle incoming mail via mpop with mail clients that insist on using POP3. See
       the EXAMPLES section below.
       Mpopd listens on 127.0.0.1 port 1100 by default, but can also run without  its  own  network  sockets  in
       inetd mode, where it handles a single POP3 session on standard input / output.
       To  prevent  abuse,  mpopd  will  allow  only  a  limited  number  of  concurrent  POP3  sessions, and an
       authentication failure occurrs, future authentication requests in any POP3 session will  (for  a  limited
       duration) only be answered after a small delay.

OPTIONS

       --version
              Print version information

       --help Print help

       --inetd
              Start single POP3 session on stdin/stdout

       --interface=ip
              Listen on the given IPv6 or IPv4 address instead of 127.0.0.1

       --port=number
              Listen on the given port number instead of 25

       --log=none|syslog|filename
              Set logging: none (default), syslog, or logging to the given file.

       --auth=user[,passwordeval]
              Require  authentication  with  this  user  name.  The  password  will  be retrieved from the given
              passwordeval command (this works just like passwordeval in mpop) or, if none is  given,  from  the
              key ring or, if that fails, from a prompt.

       --maildir=dir
              Use this maildir as the mailbox.

EXAMPLES

       Using mpopd to handle incoming mail for a POP3-based mail client
       Some  mail  clients  cannot get incoming mail from local files and instead insist on using a POP3 server.
       You can configure mpopd to be that POP3 server and serve your incoming mail from a local maildir folder.
       (Similarly, some mail clients cannot send outgoing mail via a program such as msmtp and instead insist on
       using an SMTP server.  You can configure msmtpd to be that SMTP server and hand the mail over  to  msmtp.
       See the relevant section in the msmtp manual.)
       For  this  purpose,  mpopd  should listen on an unprivileged port, e.g. 1100 (the default).  A mailbox is
       defined using first the --auth option to set a user name and password and then using the --maildir option
       to specify the maildir folder that holds the incoming mail.  Multiple such option pairs can  be  used  to
       define  multiple  mailboxes, e.g. from different remote mail accounts.  Programs such as mpop can deliver
       new mail into the maildir folders at any time, but as long as mpopd is  running  no  other  programs  may
       alter or remove mails from these folders.
       Let's use the user name mpopd-user. You have two options to manage the password:

              Store  the  password  in  your  key ring, e.g. with secret-tool store --label=mpopd host localhost
              service pop3 user mpopd-user.  In this case, use the mpopd option --auth=mpopd-user.

              Store the password in an encrypted file and use the passwordeval mechanism. Example for gpg: mpopd
              ... --auth=mpopd-user,'gpg -q -d ~/.mpopd-password.gpg'

       The    complete    command    then    is     (using     the     keyring):     mpopd     --auth=mpopd-user
       --maildir=/path/to/your/maildir/folder
       The  mail  client  software  must  then be configured to use localhost at port 1100 for incoming mail via
       POP3, and to use authentication with user mpopd-user and the password you chose.  The  mail  client  will
       probably  complain  that  the POP3 server does not support TLS, but in this special case that is ok since
       all communication between your mail client and mpopd will stay on the local machine.

SEE ALSO

       mpop(1)

                                                     2021-09                                            MPOPD(1)