man qpopper Command

Man page for apt-get qpopper Command

Man Page for qpopper in Linux

Ubuntu Man Command : man qpopper

Man Qpopper  Command

This tutorial shows the man page for man qpopper in linux.

Open terminal with 'su' access and type the command as shown below:
man qpopper

Result of the Command Execution shown below:

qpopper(8)                                                          qpopper(8)

qpopper POP3 server (v4.0)

/usr/local/lib/popper [ [ address ] [ : ] [ port ] ]
[ b buildir ] [ c ] [ d ] [ D drac host ]
[ e login_delay=nn,expire=nn ] [ f config file ]
[ k ] [ K service ] [ l0|1|2 ] [ p0|1|2|3|4 ]
[ R ] [ s ] [ S ] [ t trace file ] [ T timeout ]
[ u ] [ U ] [ v ] [ V ] [ x ] [ y log facility ]

This man page may be out of date. Please see the Administrator's Guide
included in the distribution or on the Qpopper web site at www.qpop

Qpopper is a POP3 server to enable POP3 clients to read and download
mail. This server implements the POP protocol defined in RFC 1939 and
the RFC 2449 extensions. This implementation runs on a variety of Unix
platforms, including Linux.

The server also enables clients to send mail using XTND XMIT, which is
processed via sendmail(8).

If compiled as a standalone daemon (instead of being run from
inetd), you can can specify the IP address and/or port number to
bind to at run time as parameter 1, e.g., 'popper S' or 'popper 8110 S T600'. If IPv6 support
is compiled in, address can be also IPv6 address by enclosing
the address with `[' and `]'. If not specified, the IP address
defaults to all available. The default port is 110 except when
_DEBUG (not simply DEBUG) is defined, then it is 8765.

See the Administrator's Guide file for more information on
standalone mode.

b bulldir
Turns on the bulletin feature and specifies the bulletin direc
tory path. The command line overrides the compiled value if it
is defined. To enable bulletins by default and specify a
default bulletin directory during compilation, include the
enable bulletins=bull directory flag when running ./configure.
The usual bulletin directory is /var/spool/bulls.

A bulletin database can be used to track the bulletins instead
of the users' home directory. This feature is enabled by
including the enable bulldb=bull directory flag when running

c Downcases user names. This permits users to configure their
clients with user names in UPPER or MiXeD case, and still login,
assuming their actual user name is all lower case.

d Turns on debug logging if compiled (pass enable debugging to
./configure). All debugging information is saved using sys
log(8). If this option is used, it should be first, so that
debug records are generated for subsequent options.

D drac host
If compiled with enable drac, specifies the drac host.
Defaults to localhost.

e x=value,...
Sets POP3 extensions. Sets x to the specified value. Used to
include Login Delay and/or Expire response tags to the CAPA com

Remember neither Expire nor Login Delay is enforced by qpopper;
Sysadmins have to implement them by some other means. However,
you can enforce EXPIRE 0 (no retention at all) by using the
enable auto delete flag with ./configure. This causes mes
sages to be automatically deleted after they are downloaded.

f config file
Reads additional run time options from config file. See Config
File Options for option names and syntax.

k Enables Kerberos authentication when qpopper has been compiled
with with kerberos5. You must already have libraries that
support Kerberos.

K service
The specified Kerberos service is used instead of the compiled
in value. The default is rcmd, but pop is also common.

l 0|1|2
Sets TLS/SSL handling. Must have compiled with OpenSSL or SSL

0 is the default. TLS/SSL is not supported.

1 enables the STLS command. This permits a client to attempt
TLS/SSL negotiation after connecting.

2 Causes Qpopper to attempt TLS negotiation when a client first
connects. This is for alternate port support.

p 0|1|2|3|4
Sets plain text password handling options. To use this option,
you must have an alternative to plain text passwords available,
such as APOP.

0 is the default, which permits plain text passwords only for
those users who are not in the APOP database.

1 disables plain text passwords for all users, even those who
are not in the APOP database.

2 permits plain text passwords for all users, even those who are
in the APOP database (this allows clients to fall back on plain
text authentication if they do not support APOP).

3 allows plain text passwords only for connections on the loop
back (127.*.*.*) address.

4 permits plain text passwords only if TLS/SSL has been negoti
ated for the session (requires an executable compiled with
OpenSSL or SSL Plus).

R Disables reverse lookups on client IP addresses.

t trace file
Turns on debug logging if compiled (pass enable debugging to
./configure) and writes the trace information in trace file
using fprintf(3V). If this option is used, it should be first,
so that debug records are generated for subsequent options.

s Turns on statistics logging using syslog(8) or trace file. At
the end of each popper session, the following information is
logged: username, number of messages deleted, number of bytes
deleted, number of message left on server, number of bytes left
on server.

S Enables server mode. This mode reduces disk I/O and disk space
usage when popper is used on a system that serves POP only users

T timeout
option changes the default compiled value POP_TIMEOUT for termi
nating a session with a pop client.

When the server is waiting for a command to arrive from the
client, it times out after the specified number of seconds and
terminates the session. This avoids having popper processes
hang forever waiting for command input from clients which have
terminated abnormally or are hung.

A small value is ok for small to medium networks where the net
work delay is within a few seconds. In this case 15 30 seconds
is not unreasonable. Networks with large delays in sending
packets (e.g., SLIP links) may require a larger value. In this
case 300 seconds (5 minutes) is not unreasonable.

Note that RFC 1939 requires a minimum of 600 second (10 min

u After a user authenticates, process options from a file called
.qpopper options in the user's home directory. This file can be
owned by and writable by the user.

U After a user authenticates, process options from a file called
..qpopper options in the spool directory, where is
the user name. This file should not be owned by nor writable by
the user.

v Report the current version and exit.

V Report the current version and exit.

x Disable use of XTND XMIT. NOTE: Administrators are strongly
encouraged to disable XTND XMIT in favor of mechanisms such as

y log facility

Processing Options are described below.

Processing Options
Here are some options the values of which are announced to clients.
Syntax of the options is:


This sets option opt to be value. Multiple options can be specified at
one instance and are comma separated.

The following are the options supported:

Config File Options
You can set Qpopper run time options either from the command line or in
a configuration file.

Configuration files use different option names and a different syntax
than the command line (because command line options are limited to one

The general syntax of the config file (in ABNF) is:

config line ::= comment line / reset line / set line

comment line ::= "

Related Topics

Apt Get Commands