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.IX Title "Mail::SpamAssassin::Plugin::DCC 3"
.TH Mail::SpamAssassin::Plugin::DCC 3 2026-07-23 "perl v5.42.2" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.nh
.SH NAME
Mail::SpamAssassin::Plugin::DCC \- perform DCC check of messages
.SH SYNOPSIS
.IX Header "SYNOPSIS"
.Vb 1
\&  loadplugin Mail::SpamAssassin::Plugin::DCC
\&
\&  full DCC_CHECK        eval:check_dcc()
\&  full DCC_CHECK_50_79  eval:check_dcc_reputation_range(\*(Aq50\*(Aq,\*(Aq79\*(Aq)
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
The DCC or Distributed Checksum Clearinghouse is a system of servers
collecting and counting checksums of millions of mail messages.
The counts can be used by SpamAssassin to detect and filter spam.
.PP
See https://www.dcc\-servers.net/dcc/ for more information about DCC.
.PP
Note that DCC is disabled by default in \f(CW\*(C`v310.pre\*(C'\fR because its use requires
software that is not distributed with SpamAssassin and that has license
restrictions for certain commercial uses.
See the DCC license at https://www.dcc\-servers.net/dcc/LICENSE for details.
.PP
Enable it by uncommenting the "loadplugin Mail::SpamAssassin::Plugin::DCC"
confdir/v310.pre or by adding this line to your local.pre.  It might also
be necessary to install a DCC package, port, rpm, or equivalent from your
operating system distributor or a tarball from the primary DCC source
at https://www.dcc\-servers.net/dcc/#download
See also https://www.dcc\-servers.net/dcc/INSTALL.html
.SH TAGS
.IX Header "TAGS"
The following tags are added to the set, available for use in reports,
header fields, other plugins, etc.:
.PP
.Vb 4
\&  _DCCB_    DCC server ID in X\-DCC\-*\-Metrics header field name
\&  _DCCR_    X\-DCC\-*\-Metrics header field body
\&  _DCCREP_  DCC Reputation or percent bulk mail (0..100) from
\&              commercial DCC software
.Ve
.SH "USER SETTINGS"
.IX Header "USER SETTINGS"
.IP "use_dcc (0|1)		(default: 1)" 4
.IX Item "use_dcc (0|1) (default: 1)"
Whether to use DCC, if it is available.
.IP "use_dcc_rep (0|1)		(default: 1)" 4
.IX Item "use_dcc_rep (0|1) (default: 1)"
Whether to use the commercial DCC Reputation feature, if it is available. 
Note that reputation data is free for all starting from DCC 2.x version,
where it\*(Aqs automatically used.
.IP "dcc_body_max NUMBER" 4
.IX Item "dcc_body_max NUMBER"
.PD 0
.IP "dcc_fuz1_max NUMBER" 4
.IX Item "dcc_fuz1_max NUMBER"
.IP "dcc_fuz2_max NUMBER" 4
.IX Item "dcc_fuz2_max NUMBER"
.PD
Sets how often a message\*(Aqs body/fuz1/fuz2 checksum must have been reported
to the DCC server before SpamAssassin will consider the DCC check hit.
\&\f(CW999999\fR is DCC\*(Aqs MANY count.
.Sp
The default is \f(CW999999\fR for all these options.
.IP "dcc_rep_percent NUMBER" 4
.IX Item "dcc_rep_percent NUMBER"
Only the commercial DCC software provides DCC Reputations (but starting from
DCC 2.x version it is available for all).  A DCC Reputation is the
percentage of bulk mail received from the last untrusted relay in the path
taken by a mail message as measured by all commercial DCC installations. 
See http://www.rhyolite.com/dcc/reputations.html You \f(CW\*(C`must\*(C'\fR whitelist your
trusted relays or MX servers with MX or MXDCC lines in /var/dcc/whiteclnt as
described in the main DCC man page to avoid seeing your own MX servers as
sources of bulk mail.  See
https://www.dcc\-servers.net/dcc/dcc\-tree/dcc.html#White\-and\-Blacklists The
default is \f(CW90\fR.
.SH "ADMINISTRATOR SETTINGS"
.IX Header "ADMINISTRATOR SETTINGS"
.IP "dcc_timeout n		(default: 5)" 4
.IX Item "dcc_timeout n (default: 5)"
How many seconds you wait for DCC to complete, before scanning continues
without the DCC results. A numeric value is optionally suffixed by a
time unit (s, m, h, d, w, indicating seconds (default), minutes, hours,
days, weeks).
.IP "dcc_home STRING" 4
.IX Item "dcc_home STRING"
This option tells SpamAssassin where to find the dcc homedir.
If not specified, try to use the locally configured directory
from the \f(CW\*(C`cdcc homedir\*(C'\fR command.
Try /var/dcc if that command fails.
.IP "dcc_dccifd_path STRING" 4
.IX Item "dcc_dccifd_path STRING"
This option tells SpamAssassin where to find the dccifd socket instead
of a local Unix socket named \f(CW\*(C`dccifd\*(C'\fR in the \f(CW\*(C`dcc_home\*(C'\fR directory.
If a socket is specified or found, use it instead of \f(CW\*(C`dccproc\*(C'\fR.
.Sp
If specified, \f(CW\*(C`dcc_dccifd_path\*(C'\fR is the absolute path of local Unix socket
or an INET socket specified as \f(CW\*(C`[Host]:Port\*(C'\fR or \f(CW\*(C`Host:Port\*(C'\fR.
Host can be an IPv4 or IPv6 address or a host name
Port is a TCP port number. The brackets are required for an IPv6 address.
.Sp
The default is \f(CW\*(C`undef\*(C'\fR.
.IP "dcc_path STRING" 4
.IX Item "dcc_path STRING"
Where to find the \f(CW\*(C`dccproc\*(C'\fR client program instead of relying on SpamAssassin
to find it in the current PATH or \f(CW\*(C`dcc_home/bin\*(C'\fR. This must often be set,
because the current PATH is cleared by \fItaint mode\fR in the Perl interpreter,
.Sp
If a \f(CW\*(C`dccifd\*(C'\fR socket is found in \f(CW\*(C`dcc_home\*(C'\fR or specified explicitly
with \f(CW\*(C`dcc_dccifd_path\*(C'\fR, use the \f(CWdccifd(8)\fR interface instead of \f(CW\*(C`dccproc\*(C'\fR.
.Sp
The default is \f(CW\*(C`undef\*(C'\fR.
.IP "dcc_options options" 4
.IX Item "dcc_options options"
Specify additional options to the \fBdccproc\fR\|(8) command.  Only
characters in the range [0\-9A\-Za\-z ,._/\-] are allowed for security reasons.
.Sp
The default is \f(CW\*(C`undef\*(C'\fR.
.IP "dccifd_options options" 4
.IX Item "dccifd_options options"
Specify additional options to send to the dccifd daemon with
the ASCII protocol described on the \fBdccifd\fR\|(8) man page.
Only characters in the range [0\-9A\-Za\-z ,._/\-] are allowed for security reasons.
.Sp
The default is \f(CW\*(C`undef\*(C'\fR.
.IP "dcc_learn_score n		(default: undef)" 4
.IX Item "dcc_learn_score n (default: undef)"
Report messages with total scores this much larger than the
SpamAssassin spam threshold to DCC as spam.