Problems Associated with Old DCC Software
The Distributed Checksum Clearinghouses or
DCC is an anti-spam content filter
that runs on a variety of
operating systems.
It has been in use at many sites since 2000.
Third parties have been redistributing copies of the DCC software for many
years.
It is unfortunate and surprising
that third parties of them are still redistributing ancient and
obsolete versions that were current in 2005.
It is less surprising that many installations are running obsolete
versions.
See the main DCC web page for information about the
current version.
Finding the Version Number
The version of DCC software on a computer can be determined with
the cdcc -V or
dccproc -V command.
The versions of software used by clients of a DCC server can be
inferred from the output of the
cdcc "clients -V".
The column labeled "v" shows the version of the DCC client-server protocol
used by each client of a DCC server.
The current protocol is version 9.
Clients using protocol version 8 or older should be upgraded.
If the cdcc -V command
reports a version older than 1.3.80,
then you are using a version of DCC software released in 2007 or before.
The checksums it computes for some mail messages probably differ from
the checksums computed by most DCC installations,
and so DCC is less effective for you.
If the cdcc -V command
reports a version older than 1.3.25, then you are using a version of
DCC software released in 2005 or before.
Besides being like all versions older than 2007,
your version has problems talking to DCC servers.
It tries too hard to recover from network problems and so can trigger
the automatic DoS defenses of the public DCC servers.
Those defenses start with
delaying responses to clients that make too many requests.
Eventually requests from troublesome clients are entirely ignored.
Upgrading
If it has not been broken when repackaged by a third party,
the shell script in /var/dcc/libexec/updatedcc (or in some
cases in /usr/local/etc/libexec/updatedcc, /etc/dcc/libexec/updatedcc, or
elsewhere) will fetch, configure, build, install, and restart the DCC software.
If necessary,
see the main DCC web page for a tarball
of the current version.
Contact Vernon Schryver at
vjs@rhyolite.com
or using the
form.
Do not send mail to the spam trap.
$Date: 2010/04/16 21:18:34 $