To make SpamAssassin use DCC, uncomment the following line in the v310.pre file so the plugin gets loaded:
I've installed DCC but I never seem to get DCC hits, even though I should. Why?
If you have installed DCC, and are running spamassassin or spamd without the "-L" switch, you should be seeing hits in spam reports.
Check your firewall setup. 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:
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.
Assuming you allow all outbound packets out of your machine, you only need to add an INPUT rule to your /etc/sysconfig/iptables file. Add the following line in your INPUT chain, above any REJECT rules:
-A <chain-name> -p udp -m udp --dport 1024:65535 --sport 6277 -j ACCEPT
DCC does not give hits in spamd
If DCC gives hits when run with "spamassassin" from the command-line, but not from spamd, you may have a PATH issue where the DCC client cannot be found in spamd's path.
Add the path to your dccproc tool to the local.cf file:
Very detailed instructions on configuring DCC for a personal Unix account are in SingleUserUnixInstall.