.\" (c) 2002-2003 Andreas Krennmair <ak@synflood.at>
.\" $Id: akpop3d.8,v 1.12 2003/07/27 16:51:25 ak Exp $
.Dd April 4, 2003
.Dt AKPOP3D 8
.Os "akpop3d"
.Sh NAME
.Nm akpop3d
.Nd small and secure POP3 daemon
.Sh SYNOPSIS
.Nm akpop3d
.Op Fl s
.Op Fl p Ar port
.Op Fl d
.Op Fl f Ar pidfile
.Op Fl c Ar certfile
.Op Fl k Ar keyfile
.Op Fl l Ar address
.Op Fl a Ar authfile
.Op Fl m Ar spooldir
.Op Fl D
.Op Fl L Ar mboxfile
.Op Fl t Ar timeout
.Op Fl x Ar tmpdir
.Op Fl v
.Op Fl h
.Sh DESCRIPTION
.Nm
is a small and secure implementation of a server for
.B Post Office Protocol Version 3
as described in
.%T RFC1939.
Furthermore, POP3-over-SSL for secure retrieval of email is also supported.
.Pp
.Nm
must be started as root. It then listens for connections on port 110. When
the commandline switch
.Fl s
is used, POP3-over-SSL is enabled, and
.Nm
listens on port 995.
.Pp
.Nm
is usually started via some kind of startup script, which depends on your Unix
system. Init scripts for Debian and Red Hat systems are provided with the
source package.
.Sh OPTIONS
.Nm
accepts the following commandline switches:
.Bl -tag
.It Fl d
Run as a daemon (in the background). The process ID of the daemon is written to
a PID file, which by default is
.Pa /var/run/akpop3d.pid
but which can be changed using the
.Fl f
option.
.It Fl f Ar pidfile
Store the process ID of the daemon in
.Ar pidfile
which must be specified as a full path (i.e.
.Pa /path/to/something
instead of
.Pa something
on its own).
.It Fl s
SSL mode: instead of listening on port 110,
.Nm
will listen on port 995 and will use SSL to encrypt communications. The
certificate and key will be taken from
.Pa /etc/akpop3d/cert.pem
and
.Pa /etc/akpop3d/key.pem
respectively unless set with the
.Fl c
and
.Fl k
options.
.It Fl c Ar certfile
Use
.Ar certfile
for the SSL certificate. (Point this to your SSL certificate.)
.It Fl k Ar keyfile
Use
.Ar keyfile
for the SSL key. (Point this to your RSA key.)
.It Fl p Ar port
Listen on the given
.Ar port
instead of port 995 (SSL) or 110 (non-SSL).
.It Fl l Ar address
Listen on the given
.Ar address
instead of not binding to a specific IP address.
.It Fl a Ar authfile
Instead of using
.Pa /etc/passwd
for authentication, read information from the
.Ar authfile
text file. The format of this file is
.Li username:password:unixname:maildrop
(one record per line), where
.Ar username
is the POP3 username,
.Ar password
is the POP3 password,
.Ar unixname
is the Unix username to run as when reading the mailbox, and
.Ar maildrop
is the full path to the maildrop file to use for that user. Note that as with
the
.Fl f
option,
.Ar authfile
must be specified as a full path.
.Pp
The password may be given either as an MD5 hash or in the clear (not
recommended).  If MD5 us used, the value should be "MD5-" followed by
32 hexadecimal digits (lower case) representing the MD5 output of the
following string: The password, a line feed (ASCII 10), the user name,
a line feed, and the magic string "akpop3d".  No trailing line feed
after the magic string.  As an example, the password "foo" for user
"bar" would be "MD5-a199706d2b8302a086a20fe9fb4e8403".
.Pp
If the programs printf and md5sum are available, which they typically
are on GNU-based systems, the hash may be calculated using the
following command:
.Pp
    printf "foo\\nbar\\nakpop3d" | md5sum
.It Fl m Ar spooldir
specifies an alternative mail spool directory. The default is 
.Pa /var/mail/ .
.It Fl D
enables using the files /etc/pop3.allow and /etc/pop3.deny for specifying users
that are allowed to receive email via POP3.
.It Fl L Ar mboxfile
uses the file
.Ar mboxfile
in the user's home directory as mailspool.
.It Fl t Ar timeout
sets a timeout of
.Ar timeout
seconds for read and write operations. The default is 30 seconds.
.It Fl x Ar tmpdir
set the default temporary directory to
.Ar tmpdir .
.It Fl v
Show the program version and exit.
.It Fl h
Show a summary of program options and exit.
.El
.Sh SEE ALSO
.Xr popa3d 8
.Rs
.%T "RFC 1939 - Post Office Protocol - Version 3"
.Re
.Sh HISTORY
The current POP3 protocol standard was published in May 1996. It was preceded
by POP2 (February 1985) and POP (October 1984).
.Sh AUTHORS
Andreas Krennmair <ak@synflood.at>
.Pp
Andrew Wood <andrew.wood@ivarch.com>