TMDA (tagged message delivery agent)
is the free answer to your spam woes. Unlike other filters that look for
keywords such as "viagra", "sweepstakes", and
"lesbians"; TMDA uses a simple, but highly reliable method for
determining which e-mails come from real people... it asks them!
TMDA asks people if they are real?
Yes, it is called a "challenge/response method". When someone
sends mail to a TMDA guarded e-mail address for the first time, instead of
just blindly dumping the message in your in-box, TMDA puts it in a special
quarantine area and sends a
"challenge" back to the author.
The challenge is just an e-mail that briefly explains the system and asks the
user to reply to the challenge (this is the "response" part). Once
TMDA receives the response, it releases the original message from quarantine
and adds the sender to a list of people from which it will accept mail. Any
future messages from that user will be accepted without another
How does that help?
Spammers typically put fake e-mail addresses on their spam. They don't want
you to reply to them. The address they use is bad, so they never receive
TMDA's challenge, they never get to respond, the message is never released
from quarantine, and it never makes it to your in-box. Instead, it sits
around and gathers dust until the system throws it away.
Great! How do I get it!
tmda-cgi is designed to run on your mail server. It does not run on your
- If you are a system administrator who has not yet installed TMDA, start
by surfing up TMDA's website.
- If you are a system administrator who has installed TMDA, but has not yet
installed tmda-cgi, start by surfing up the install
- If you are not a system administrator, and you do not know if your mail
server is running tmda-cgi, contact your sysadmin and ask them to install
tmda-cgi for you. Give them this URL if they do not have it.
If you've already got tmda-cgi, proceed onto the FAQ to learn more about how it all works!