An effective tool for dealing with spam is to implement greylisting on your port 25 SMTP service. For a good explanation of how this works, see John Simpon's jgreylist webpage.
Decide which version you want to install - Perl or C. The C version is faster for busier servers
- Perl version
The jgreylist script needs to be installed where the SMTP run script can find it. Easiest place is the /var/qmail/bin directory:
The script should be owned by root, have the same group ID as the greylist user's group ID, and have permissions 0750. With these server install instructions, the group is nofiles.
chmod 0750 jgreylist
