TMDA (http://tmda.net) CGI Interface

Frequently Asked Questions

Is it really free?
Won't this challenge/response thing annoy people who send me mail?
Can I look at the messages in quarantine to make sure I'm not missing something important?
What about my mailing list and joke of the day? How will that get past TMDA?
What about people I send mail to, do they get challenged as well?
What if I change my mind? Can I get rid of TMDA easily?

Is it really free?

Yes, both TMDA and tmda-cgi (the program that lets you configure TMDA with your web browser) are free. The programmers who created it volunteered their time because they hate spam that much.

Won't this challenge/response thing annoy people who send me mail?

A little, perhaps. But I think you'll see that the inconvenience is slight and since other users only have to confirm once, they won't mind doing it to help you stay spam-free. You'd reply to a message to make them spam-free, wouldn't you?

Also, you can edit the list that TMDA uses to determine whether messages get challenged. If you really think that replying to confirmation messages will annoy your friends, you can put their addresses on the list pre-emptively and they'll never notice a difference.

Can I look at the messages in quarantine to make sure I'm not missing something important?

Yes, tmda-cgi has a feature that lets you look at quarantined mail. TMDA calls this your "pending" directory. You can even select the whitelist button associated with a message to release it, and allow future mail from that source to be accepted without challenge.

What about my mailing list and joke-of-the-day? How will that get past TMDA?

There are two simple ways to tell TMDA to accept mail from a particular automated source:

  • For automated mailings that always come from the same e-mail address (such as a joke-of-the-day mailing), simply add the sender's e-mail address to your list. Any future mailings from that address will be accepted without a challenge.

    This is nice because if joke-of-the-day (or whomever) sells off your address to a spammer, you still won't receive any spam. The spammer will almost certainly send the spam from a different address than the one you listed.

  • Mailing lists require a slightly different tactic. Since the posts come from all sorts of different addresses, the easiest solution is to create a "keyword" address and use that when you sign up for the list.

    Suppose you wanted to join a mailing list about quilters. Instead of signing up with your real e-mail address (let's say it is joe@i.love.quilts.com), you can use tmda-cgi to generate a keyword address such as joe-keyword-quilters.092a48@i.love.quilts.com and use that when you sign up (yes, it is a pretty long address, but you can generally copy and paste it). Any e-mail that arrives to this address will be accepted.

    Keyword addresses are a bit like giving out a key to your mailbox. Anyone can send mail to them. If the a spammer gets a hold of a keyword address, they can start spamming you again. However, locks are easily changed and keywords are easily revoked. If you start receiving spam directed to joe-keyword-quilters.092a48@i.love.quilts.com, you'll know it leaked out from your quilters mailing list. You can revoke the address and either sign up again to the mailing list with a new keyword address, or revoke the keyword and find some other place to get your fix of quilting news.

What about people I send mail to, do they get challenged as well?

No, people you write to do not generally have to confirm anything. If you send mail from a TMDA-guarded account to someone who is not on your list, TMDA can be configured to automatically make up a new "dated" address and use that. Unlike keyword addresses that code a word into the address (see above), dated addresses code an expiration time into the address (five days, for example). If the user replies to your e-mail within that time, they won't have to confirm.

Dated addresses are generally transparent and fairly safe. If a spammer gets a hold of one, they can only use it until it expires. Any mail sent to an expired address typically generates a confirmation notice, as if they sent mail to your regular address.

In other words, you can send mail to someone, they can reply, you can reply to them, and so on for as long as you wish without anyone ever having to confirm. If they take too long to reply, they would have to confirm then, but again, only once. At that point they would be on your list and TMDA would accept mail from them without a challenge.

What if I change my mind? Can I get rid of TMDA easily?

Yes, there is an uninstall option on the tmda-cgi menu, under "settings".

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