Mail::SpamAssassin::Plugin::DCC − perform DCC check of messages


  loadplugin     Mail::SpamAssassin::Plugin::DCC
  full DCC_CHECK        eval:check_dcc()
  full DCC_CHECK_50_79  eval:check_dcc_reputation_range('50','79')


The DCC or Distributed Checksum Clearinghouse is a system of servers collecting and counting checksums of millions of mail messages. counts can be used by SpamAssassin to detect and reject or filter spam.

Because simplistic checksums of spam can be easily defeated, the main DCC checksums are fuzzy and ignore aspects of messages. The fuzzy checksums are changed as spam evolves.

Note that DCC is disabled by default in "init.pre" because it is not open source. See the DCC license for more details.

See−spam/dcc/ for more information about DCC .


The following tags are added to the set, available for use in reports, header fields, other plugins, etc.:

  _DCCB_    DCC server ID in a response
  _DCCR_    response from DCC − header field body in X−DCC−*−Metrics
  _DCCREP_  response from DCC − DCC reputation in percents (0..100)

Tag _DCCREP_ provides a nonempty value only with commercial DCC systems. This is the percentage of spam vs. ham sent from the first untrusted relay.


use_dcc (0|1) (default: 1)

Whether to use DCC , if it is available.

dcc_body_max NUMBER
dcc_fuz1_max NUMBER
dcc_fuz2_max NUMBER

This option sets how often a message’s body/fuz1/fuz2 checksum must have been reported to the DCC server before SpamAssassin will consider the DCC check as matched.

As nearly all DCC clients are auto-reporting these checksums, you should set this to a relatively high value, e.g. 999999 (this is DCC ’s MANY count).

The default is 999999 for all these options.

dcc_rep_percent NUMBER

Only commercial DCC systems provide DCC reputation information. This is the percentage of spam vs. ham sent from the first untrusted relay. It will hit on new spam from spam sources. Default is 90.


dcc_timeout n (default: 8)

How many seconds you wait for DCC to complete, before scanning continues without the DCC results.

dcc_home STRING

This option tells SpamAssassin where to find the dcc homedir. If not given, it will try to get dcc to specify one, and if that fails it will try dcc’s own default homedir of ’/var/dcc’. If "dcc_path" is not specified, it will default to looking in "dcc_home/bin" for dcc client instead of relying on SpamAssassin to find it in the current PATH . If it isn’t found there, it will look in the current PATH . If a "dccifd" socket is found in "dcc_home" or specified explicitly, it will use that interface instead of "dccproc".

dcc_dccifd_path STRING

This option tells SpamAssassin where to find the dccifd socket. If "dcc_dccifd_path" is not specified, it will default to looking for a socket named "dccifd" in a directory "dcc_home". The "dcc_dccifd_path" can be a Unix socket name (absolute path), or an INET socket specification in a form "[host]:port" or "host:port", where a host can be an IPv4 or IPv6 address or a host name, and port is a TCP port number. In case of an IPv6 address the brackets are required syntax. If a "dccifd" socket is found, the plugin will use it instead of "dccproc".

dcc_path STRING

This option tells SpamAssassin specifically where to find the "dccproc" client instead of relying on SpamAssassin to find it in the current PATH . Note that if taint mode is enabled in the Perl interpreter, you should use this, as the current PATH will have been cleared.

dcc_options options

Specify additional options to the dccproc(8) command. Please note that only characters in the range [0−9A−Za−z ,._/−] are allowed for security reasons.

The default is "undef".

dccifd_options options

Specify additional options to send to the dccifd(8) daemon. Please note that only characters in the range [0−9A−Za−z ,._/−] are allowed for security reasons.

The default is "undef".

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