=head1 Qpsmtpd configuration

The default way of setting config values is placing files with the
name of the config variable in the config directory F<config/>, like
qmail's F</var/qmail/control/> directory. NB: F</var/qmail/control> (or
F<$ENV{QMAIL}/control>) is used if a file does not exist in C<config/>.
The location of the C<config/> directory can be set via the
I<QPSMTPD_CONFIG> environment variable and defaults to the current
working directory.

Any empty line or lines starting with C<#> are ignored. You may use a
plugin which hooks the C<config> hook to store the settings in some other
way. See L<docs/plugins.pod> and L<docs/hooks.pod> for more info on this.
Some settings still have to go in files, because they are loaded before
any plugin can return something via the C<config> hook: C<me>, C<logging>,
C<plugin_dirs> and of course C<plugins>. B<FIXME: more?>

=head2 Core settings

These settings are used by the qpsmtpd core. Any other setting is (hopefully)
documented by the corresponding plugin. Some settings of important plugins
are shown below in L</Plugin settings>.

=over 4

=item plugins

The main config file, where all used plugins and their arguments are listed.

=item me

Sets the hostname which is used all over the place: in the greeting message,
the I<Received: >header, ...
Default is whatever Sys::Hostname's hostname() returns.

=item plugin_dirs

Where to search for plugins (one directory per line), defaults to F<./plugins>.

=item logging

Sets the primary logging destination, see F<plugins/logging/*>. Format
is the same as it's used for the F<plugins> config file. B<NOTE:> only
the first non empty line is used (lines starting with C<#> are counted
as empty).

=item loglevel

This is not used anymore, I<only> if no F<logging/> plugin is in use. Use a
logging plugin.

=item databytes

Maximum size a message may be. Without this setting, there is no limit on the
size. Should be something less than the backend MTA has set as it's maximum
message size (if there is one).

=item size_threshold

When a message is greater than the size given in this config file, it will be
spooled to disk. You probably want to enable spooling to disk for most virus
scanner plugins and F<spamassassin>.

=item smtpgreeting

Override the default SMTP greeting with this string.

=item spool_dir

Where temporary files are stored, defaults to F<~/tmp/>.

=item spool_perms

Permissions of the I<spool_dir>, default is C<0700>. You probably have to
change the defaults for some scanners (e.g. the F<clamdscan> plugin).

=item timeout

=item timeoutsmtpd

Set the timeout for the clients, C<timeoutsmtpd> is the qmail smtpd control
file, C<timeout> the qpsmtpd file. Default is 1200 seconds.

=item tls_before_auth

If set to a true value, clients will have to initiate an SSL secured
connection before any auth succeeds, defaults to C<0>.

=back

=head2 Plugin settings

=over 4

=item rcpthosts, morercpthosts

Plugin: I<rcpt_ok>

Domains listed in these files will be accepted as valid local domains,
anything else is rejected with a C<Relaying denied> message. If an entry
in the C<rcpthosts> file starts with a C<.>, mails to anything ending with
this string will be accepted, e.g.:

 example.com
 .example.com

will accept mails for C<user@example.com> and C<user@something.example.com>.
The C<morercpthosts> file is just checked for exact (case insensitive)
matches.

=item hosts_allow

Plugin: F<hosts_allow>.

Don't use this config file. The plugin itself is required to set the
maximum number of concurrent connections. This config setting should
only be used for some extremly rude clients: if list is too big it will
slow down accepting new connections.

=item relayclients
=item morerelayclients

Plugin: F<check_relay>

Allow relaying for hosts listed in this file. The C<relayclients> file accepts
IPs and CIDR entries. The C<morercpthosts> file accepts IPs and C<prefixes>
like C<192.168.2.> (note the trailing dot!). With the given example any host
which IP starts with C<192.168.2.> may relay via us.

=item dnsbl_zones

Plugin: F<dnsbl>

This file specifies the RBL zones list, used by the dnsbl plugin. Ihe IP
address of each connecting host will be checked against each zone given.
A few sample DNSBLs are listed in the sample config file, but you should
evaluate the efficacy and listing policies of a DNSBL before using it.

See also C<dnsbl_allow> and C<dnsbl_rejectmsg> in the documentation of the
C<dnsbl> plugin

=item require_resolvable_fromhost

Plugin: F<require_resolvable_fromhost>

Reject sender addresses where the MX is unresolvable, i.e. a boolean value
is the only value in this file. If the MX resolves to something, reject the
sender address if it resolves to something listed in the
F<invalid_resolvable_fromhost> config file. The I<invalid_resolvable_fromhost>
expects IP addresses or CIDR (i.e. C<network/mask> values) one per line, IPv4
only currenlty.

=back

=cut