Would you recoomend this project?
Junk Mail Buffering Agent is a tool for preventing delivery of email until the sender has confirmed their address. It can be used in conjunction with a spam filter to prevent delivery of spammy-looking email unless the sender is confirmed as valid.
You can download file releases of jmba project from List of release files
System RequirementsOperating System: POSIX (Linux,BSD,Solaris etc..), Linux
List of release files