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.SH NAME
cucipop \- Cubic Circle POP3 daemon
.SH SYNOPSIS
.B /usr/sbin/cucipop
.RB [ \-qaYdPUSDAT ]
.RB [ "\-E \fIage\fP" ]
.RB [ "\-p \fIport\fP" ]
.br
.B /usr/sbin/cucipop
.B \-v
.ad
.SH DESCRIPTION
Cucipop is a mailbox server which is a fully compliant implementation of
Internet
.BR RFC1939 ,
Post Office Protocol Version 3.  The program allows remote access to UNIX
mailboxes.
.PP
.B Cucipop
can be started standalone or from within
.BR inetd (8).
.SH OPTIONS
.TP 0.5i
.B \-v
Cucipop will print its version number, display its compile time
configuration and exit.
.TP
.B \-q
Quiet mode, do not log statistics of regular sessions to
.BR syslogd (8).
.TP
.B \-a
Audit mode, also log statistics of regular sessions accessing empty mailboxes.
.TP
.B \-Y
Assume traditional Berkeley mailbox format, ignoring any
.B Content-Length:
fields.
.TP
.B \-d
Force interactive debug mode, accept commands from the tty.
.TP
.B \-P
Disable the optional USER and PASS command.
.TP
.B \-U
Disable the optional UIDL command.
.TP
.B \-S
Sabotage the UIDL command.  Cucipop will return different UIDL values for
every session, hence causing mailclients that attempt to leave mail on
the server to pick up the entire mailbox every time.  Turning this option on
will violate
.BR RFC1939 .
.TP
.B \-D
Autodelete messages that have been retrieved.  As soon as the QUIT command
has been received or the connection drops, cucipop will behave as if those
messages which have been collected using the RETR command were also specified
to the DELE command.
Turning this option on will violate
.BR RFC1939 .
.TP
.I "\fB\-E\fP age"
Expire (in conjunction with the
.B \-S
or
.B \-D
options)
messages that are older than
.I age
only.
.I Age
is specified in seconds.  You can increase the unit of measure by appending
an s, m, h, w, M or y.
.TP
.B \-A
Disable the optional APOP command.
.TP
.B \-T
Disable the optional TOP command.
.TP
.I "\fB\-p\fP port"
Bind to a different
.IR port .
.SH EXAMPLES
Typically
.I pop-3
service is defined in
.BR services (5)
as follows:
.Sx 1
pop-3           110/tcp
.Ex
In order to start cucipop from within
.BR inetd (8),
the following entry in
.BR inetd.conf (5)
would be suitable:
.Sx 1
pop-3   stream  tcp     nowait  root    /usr/sbin/cucipop cucipop -Y
.Ex
If your site gets many hits from popclients, it would be preferable
to start cucipop standalone as in:
.Sx 1
/usr/sbin/cucipop -Y
.Ex
Your typical BOFH setting would be:
.Sx 1
/usr/sbin/cucipop -YaSE 6w
.Ex
.SH FILES
.TP 2.3i
.B /etc/passwd
for the default authentication method
.TP
.B /var/spool/mail/$LOGNAME
system mailbox
.TP
.B /var/spool/mail/$LOGNAME.lock
lockfile for the system mailbox
.TP
.B _????`hostname`
temporary `unique' zero-length files created by cucipop
.SH "SEE ALSO"
.na
.nh
.BR RFC1939 ,
.BR RFC822 ,
.BR inetd (8),
.BR inetd.conf (5),
.BR services (5),
.BR procmail (1),
.BR mail (1),
.BR binmail (1),
.BR uucp (1),
.BR sendmail (8),
.BR biff (1),
.BR comsat (8),
.BR lockfile (1),
.BR formail (1),
.BR syslog.conf (5)
.hy
.ad
.SH BUGS
When two or more cucipop sessions are accessing the same mailbox
simultaneously,
and at least one of them tries to update the mailbox, mild mailbox corruption
might result and the other cucipop sessions will abort as soon as they
detect unaccounted mailbox changes.
The (unlikely) worst case scenario would result in some
messages not being deleted and/or gaining some trailing garbage.  Due to the
ongoing consistency checks, existing messages or content is unlikely to
be lost.
.PP
If a local mailreader alters the mailbox content after cucipop has
started and before cucipop has ended, cucipop will panic and abort
the update as soon as it detects unaccounted mailbox changes.
.PP
If the local maildelivery program is appending to the mailbox while cucipop
is starting up, and the intervals between successive writes of the same mail
are larger
than 32 seconds, then cucipop will, mistakenly, show the last message
in the mailbox (which is currently being written by the maildelivery agent)
to be shorter than
it actually is.  If the last message is marked for deletion in this
session, cucipop will notice the increased length shortly before actually
deleting the message and abort the update at that point.
.PP
The unique-id listing returned by the UIDL command is based on a hashvalue
calculated on-the-fly over the message content.  The actual values depend
on the wordsize of the machine involved (defined as uidl_t in the source).
Also, since it is
just a hashvalue (constructed out of a true hash over the entire message
and the length of the message), there is a very slight chance that it
will produce a false positive.
.PP
A continued
.B Content-Length:
field is not handled correctly.
.PP
If the TOP command is being used, the statistics of transferred
octets will become mildly inaccurate (too high, depending on the
number of untransferred newlines).
.PP
Cucipop will never create a nonexisting mailbox.
.PP
An empty first argument after a POP command is ignored (thanks to some
silly popclients that violate the standard).
.PP
When running in standalone daemon mode, an idle cucipop deamon will always
leave at least one zombie process behind.  In order to improve
performance, zombie processes are only collected when new clients
connect.
.PP
The Received field that is being tacked in front of a message misses the
trailing "; date-time" addendum to make it fully
.B RFC822
compliant.
.SH MISCELLANEOUS
Cucipop is NFS-resistant and eight-bit clean.
.PP
The format of the regular syslog statistics is as follows:
username originating-IP-address, retrieved messages (retrieved bytes),
messages left in mailbox (octets left in mailbox).
.SH NOTES
Calling up cucipop with the \-h or \-? options will cause
it to display a command-line help page.
.Sh SOURCE
Cucipop has graciously been made available by Cubic Circle and is
.Sx 1
Copyright (c) 1996, S.R. van den Berg, The Netherlands
.Ex
.\"is available at ftp.informatik.rwth-aachen.de as
.\".BR pub/packages/cucipop/cucipop.tar.gz .
.\".Sh MAILINGLIST
.\".RE
.\"If you would like to stay informed about new versions and official patches
.\"send a subscription request to
.\".RS
.\"cucipop-announce-request@cuci.nl
.\".RE
.\"(this is a readonly list).
.SH AUTHOR
Stephen R. van den Berg, Cubic Circle, The Netherlands
.RS
<srb@cuci.nl>
.\" @MY_ALT_MAIL_ADDR@
.RE
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