full-disclosure - A Report on SPAM Blackholes, Blocking/Filte ring, and AOL

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From: John.Airey at rnib.org.uk (John.Airey@...b.org.uk)
Subject: A Report on SPAM Blackholes, Blocking/Filte
	ring, and AOL

Jason, you are spot on. Provided you test that you aren't a relay yourself,
there's little you can do to prevent SPAM. 

Blackholes may refuse legitimate email from sites that aren't set up
correctly. If that site then can't email anyone at all, they are unable to
communicate with the company that blackholed them. Perhaps it would be
better to bombard their postmaster account with warnings about open relay to
give them a chance to communicate and fix it first? 

Some sites may not have reverse DNS entries for their SMTP server. Do you
refuse email from them? I've had this suggested to me before, but that would
prevent legitimate email coming just because someone messed up a reverse DNS
record. I've done it before myself and our own system rejected the outbound
email.

Filtering doesn't work, because the spammers use different techniques.
Anyone seen the latest trick, to use a Mailer-Daemon message of returned
email? It looks like a bounced message when it isn't.

The House of Commons has a filtering system which rejects emails with the
word sex in them (a little indiscriminate). However, they are debating a
Sexual Offences Bill soon, so constituents emails were being dropped about
the subject (Democracy in action? Considering that the bill would legalise
homosexual acts in public toilets but criminalise heterosexual acts almost
anywhere outside a cynic would not be surprised.)

It would be nice to think that our governments can stop SPAM through
legislation, but they really aren't interested. Which in the light of the
preceding is a little surprising.

- 
John Airey, BSc (Jt Hons), CNA, RHCE
Internet systems support officer, ITCSD, Royal National Institute of the
Blind,
Bakewell Road, Peterborough PE2 6XU,
Tel.: +44 (0) 1733 375299 Fax: +44 (0) 1733 370848 John.Airey@...b.org.uk 

A fundamentalist - what you call someone more sure of what they believe than
what you are

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