Distributed Checksum Clearinghouse
Distributed Checksum Clearinghouse (DCC) is a system of clients and servers that collect and count checksums related to mail messages. The counts can be used by SMTP servers and mail user agents to detect and reject bulk mail. DCC servers can exchange common checksums. The checksums include values that are "fuzzy", or constant across common variations in bulk messages.
| Tags | Communications Email Filters |
|---|---|
| Licenses | Free but restricted |
| Operating Systems | POSIX Windows Windows Mac OS X Unix Linux |
| Implementation | C |
Recent releases
- 26 Feb 2009 06:59
Changes: A RedHat versus Debian error message from rcDCC was quieted. An error in libexec/fetch-testmsg-whitelist was fixed.
- 10 Jan 2009 21:20
Changes: Groups of DNS blacklists that can be independently enabled in per-user whiteclnt files are supported.
- 19 Feb 2008 23:46
Changes: Deal with thrashing problems with large mmap() spaces in recent Linux kernels. Lines in log files for DNSBL hits were changed to include the IP address from the DNSBL. A DNSBL is probed only once for several -B results with distinct SMTP 4yz or 5yz rejection messages.
- 12 Jun 2007 09:58
Changes: This release improves the dccifd per-user whitelist default. It fixes the server database size estimate. Old installations really should upgrade to get the MIME decoding fix.
- 01 Feb 2007 10:41
Changes: A MIME decoding bug has been fixed that broke checksums for some now common spam and reduced the DCC hit rate. This release checks DNS NS RRs in DNSBLs for more hits and much better speed.
