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From: bk_usenet@yahoo.co.uk (BK)
Subject: Re: Mail.app Junk Filter:  Poison Spam?
Date: 16 Jan 2004 21:51:35 -0800
Message-ID: <39d9c156.0401162151.36ea5db3@posting.google.com> 
References: <whewitt-A04D86.21421112012004@news3.news.adelphia.net> 

Barbarossa <whewitt@ucsd.edu> wrote ...

> I have heard of spam being sent with text that will clog up 
> the Bayesian junk filter of Mail.app.
> 
> <Start Quote>
> 
> dementia newton postmark bootes buttercup crossover palm 
> atlantes handwrite laurent togo launder cast til contagion

[SNIP]

> <End Quote>

indeed, this is becoming more and more common and it's designed to
trick the spam filters.

However, in my experience, most of those messages aim to hide this
between bogus HTML tags so that the random text will not show up in
your mail client.

I have therefore set my SMTP server to ignore all incoming mail that
has HTML for those email accounts which are exposed to address
harvesting robots.

As a result, I only get spam once or twice a month now on those email
accounts while the SMTP server logs show that there are thousands of
messages being rejected because they contain HTML.

I have set the SMTP server to respond with an error message "HTML
email not allowed here" so if there are any false positives the sender
will be able to resend the message in plain text, which I prefer
anyway.

For me this arrangement works well because on those exposed email
addresses I can afford not to accept any HTML nor any attachments
(SMTP server also set to reject all multipart mime messages).

On my regular email addresses where I can't afford to do this I hardly
get any spam anyway because I never use them such that they would show
up on the web where the robots would see them.

Another way to fight spam, which I really like is to use a spamtrap
email address. CommuniGate Pro (CGP) has a feature by which all mail
from a sender is rejected if any TO address matches the spamtrap email
address.

All you have to do is make sure that you always quote the spamtrap
address together with your exposed address, so that robots will pick
them both up together, like this ...

me@mydomain.com (hey folks send mail to me ONLY on this address)
SPAMTRAP@mydomain.com (hey folks, NEVER send me any mail on this
address)

Any spam send to you will then be send to both addresses (typically in
the same SMTP session) and the mere existence of the spamtrap address
in the TO list will cause all mail from that sender to be rejected
right away. No matter how much care the spammer has taken to confuse
your spam filters, all their effort will have been in vain, because
they fell into the spamtrap ;-)

Of course you may not want to use the word "spamtrap" since if this
becomes a popular method of fighting spam and the spammers are not
getting any spam through anymore, then they will for sure filter out
all the addresses that contain the word "spamtrap". CGP allows you to
define any address you like as a spamtrap address.

I am sure this has been around for a while but I only just stumbled
into it when we recently migrated to CGP. Anyway, I really like the
idea and I believe it is going to be very difficult for spammers to
work around the trap. I am looking forward to see the results in the
server logs once the robots have picked up our trap addresses ;-)

rgds
bk

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