[Spamassassin Wiki] Update of "InstallingDCC" by DanielQuinlan

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The following page has been changed by DanielQuinlan:
http://wiki.apache.org/spamassassin/InstallingDCC

The comment on the change is:
new page, info from README/INSTALL

New page:
DCC (from http://www.rhyolite.com/anti-spam/dcc/)

DCC (Distributed Checksum Clearinghouse) is a system similar to Razor.
It supports fuzzy checksums and therefore detects some more spams than
Razor does at the moment.

To install it, perform the following steps:

{{{
        wget http://www.dcc-servers.net/dcc/source/dcc-dccproc.tar.Z
        tar xfvz dcc-dccproc.tar.Z
        cd dcc-dccproc-*
        ./configure && make && make install
}}}

You might want to replace the configure call with something like this to
get an FHS compliant install:

{{{
        ./configure \
            --bindir=$(PREFIX)/bin \
            --libexecdir=$(PREFIX)/lib/dcc \
            --mandir=$(PREFIX)/man \
            --homedir=/var/lib/dcc
}}}

Finally call cdcc:

{{{
        cdcc info
}}}

The last command will give some output. The output should contain lines
like this:

{{{
        dcc1.dcc-servers.net,-         RTT+0 ms    anon
        dcc2.dcc-servers.net,-         RTT+0 ms    anon
        ...
}}}

There should be *at least one*, preferably more than half a dozen, of
the public DCC servers listed.  If this is not the case, a likely
cause is an interfering firewall (see below).

Note that MIMEDefang users may need to set the 'dcc_path'
configuration setting, since MIMEDefang does not set a PATH by
default. See also 'perldoc Mail::SpamAssassin::Conf'.

Also note that DCC requires that you open your firewall for DCC reply
packets on UDP port 6277.   DCC uses UDP packets when replying, which
are blocked by most firewalls by default. As a result, it requires
that you open your firewall for DCC reply packets on UDP port 6277.
Here's sample firewall rules required:

{{{
  allow udp local gt 1023 to remote 6277
  allow udp remote 6277 to local gt 1023
}}}

If you're running a large site, processing upwards of tens of
thousands of messages a day, the DCC maintainers have requested that
you consider setting up your own DCC server as described in dccd(8),
and arrange to peer with the rest of the public servers, to reduce
their load.

More info is at UsingDcc.