Spam Filtering
CCTC is pleased to be able to offer server side filtering
for unsolicited commercial e-mail (spam).
Let's try this section in Q&A format.
Q: How is a message determined to be spam?
A: The software scans the entire message, looking for typical traits of
spam. Also, the message is compared to several world-wide databases for
reported spam and spam sources. The message is scored, based on the
traits matched against the default rules of the software. If the score
is above the limit you set, it is flagged as spam.
Q: What do you mean by "flagged"?
A: By default, the subject line of the message will be changed to start
with the special phrase "*****SPAM*****". Should you decide to
turn off
this feature, you can still filter your messages by matching against a
hidden line in the headers, "X-Spam-Flag: YES".
Q: So I need to filter the message at my system?
A: Yes. Due to the potential for false-positives (messages flagged
as
spam that actually aren't), CCTC will leave the actual filtering of the
message up to the user. This method gives you an opportunity to review
flagged messages and recover any false-positives. Instructions on how
to set up filters within your e-mail program can be found at
Q: Some good e-mail is being flagged as spam. What can I do?
A: Add the sender's e-mail address to a whitelist of users you never
want blocked. If the address is not always the same (like from some
mailing lists), you can use wildcards to allow more options. This
changes the score sufficiently that the message should never be blocked.
your username (the first part of your e-mail address) and your password.
Q: Some spam isn't getting flagged. What can I do?
A: This is a little more difficult as most spam uses a forged address.
You can try adding the sender's e-mail address to a blacklist of users
to always block, but since this will probably change on the next
mailing, it won't be terribly effective. We are working on a method to
easily add our missed spam to the world-wide databases so that they will
be caught in the future. However, if you have a spammer or list that
continues to send you unwanted e-mail from the same address, you can
certainly add them to the blacklist so that the message will be flagged
as spam every time, regardless of it's actual contents. The blacklist
Q: I've set up my lists and am not concerned about false-positives.
Is
there a way I can have the spam removed before it gets to my system?
A: Not at this time. We've already determined the method and
written
the code to make this function, but the possible issues are such that we
aren't prepared to release it to the general public at this time.
Q: Come on! I don't want to download all this junk anymore!
What kind
of issues are you talking about?
A: Well, the biggest one is that messages removed at the server are
gone completely, forever. There are no copies or backups stored.
If
any message is flagged as spam in this case, it would be deleted and you
would never know about it. So a simple mistake or oversight in your
preferences could have huge impact. Never the less, if you feel
absolutely certain in your options and are willing to take the risks,
Q: I really only want to receive e-mail from a few people. Can I
blacklist everyone except them?
A: Sort of. The easiest way is to set your "Required
Hits" to 0.
This means that every message you receive will be flagged as spam. Now
whitelist all the e-mail addresses you want to receive mail from.
These messages will not get flagged. The results are what you intended,
but the approach is different. There isn't a pure option for a global
blacklist.
Q: Where do I configure all my preferences and what do they do?
Details and examples for each option are on that site.
Q: I really like spam. Would you stop flagging it?
filtering on your account.