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:
You might want to replace the configure call with something like this to get an FHS compliant install:
It's recommended to run the persistent dccifd daemon for sites scanning more messages.
This method assumes you are not using DCC / dccifd for anything else than scanning with SA. If you are using any other features like DCC server, greylisting etc, see: https://www.dcc-servers.net/dcc/INSTALL.html
Finally call cdcc:
The last command will give some output. The output should contain lines like this:
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 UsingDcc).
More info is at UsingDcc.