---
name: "Mail::SpamAssassin::Plugin::DCC"
section: "3pm"
platform: "linux"
package: "spamassassin"
version: "4.0.2-3"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/Mail::SpamAssassin::Plugin::DCC"
---

# Mail::SpamAssassin::Plugin::DCC(3pm)

perform DCC check of messages

## NAME

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

## SYNOPSIS

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

## 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.

See https://www.dcc-servers.net/dcc/ for more information about DCC.

Note that DCC is disabled by default in `"v310.pre"` 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.

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

## TAGS

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

```
  _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
```

## USER SETTINGS

- use\_dcc (0\|1) (default: 1)

  Whether to use DCC, if it is available.

- 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's automatically used.

- dcc\_body\_max NUMBER

  - dcc\_fuz1\_max NUMBER

  - dcc\_fuz2\_max NUMBER

  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 hit. `999999` is DCC's MANY count.

  The default is `999999` for all these options.

- 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 `"must"` 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 `90`.

## ADMINISTRATOR SETTINGS

- 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).

- 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 `"cdcc homedir"` command. Try /var/dcc if that command fails.

- dcc\_dccifd\_path STRING

  This option tells SpamAssassin where to find the dccifd socket instead of a local Unix socket named `"dccifd"` in the `"dcc_home"` directory. If a socket is specified or found, use it instead of `"dccproc"`.

  If specified, `"dcc_dccifd_path"` is the absolute path of local Unix socket or an INET socket specified as `"[Host]:Port"` or `"Host:Port"`. 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.

  The default is `"undef"`.

- dcc\_path STRING

  Where to find the `"dccproc"` client program instead of relying on SpamAssassin to find it in the current PATH or `"dcc_home/bin"`. This must often be set, because the current PATH is cleared by *taint mode* in the Perl interpreter,

  If a `"dccifd"` socket is found in `"dcc_home"` or specified explicitly with `"dcc_dccifd_path"`, use the `dccifd(8)` interface instead of `"dccproc"`.

  The default is `"undef"`.

- dcc\_options options

  Specify additional options to the [**dccproc**(8)](/dccproc/8.md) command.  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 daemon with the ASCII protocol described on the [**dccifd**(8)](/dccifd/8.md) man page. Only characters in the range \[0-9A-Za-z ,.\_/-\] are allowed for security reasons.

  The default is `"undef"`.

- dcc\_learn\_score n (default: undef)

  Report messages with total scores this much larger than the SpamAssassin spam threshold to DCC as spam.