DNS Black list

[Matt Kettler]

At 02:38 AM 10/23/2003, you wrote:
>Not all spam is known to NJABL. Use SpamAssassin. Personally I would not
>trust most DNS blacklists as a single source! At least do not block mail
>just because one of the blacklists said it is spam.

Agreed, and even more importantly, DNSBLs don't have anything to do with
the message itself, they track the servers the message passed through.

This is somewhat helpful, as many systems are frequent targets of relaying
due to incompetent administration, but it does not help if the particular
mailserver has never been abused before.

In the last SpamAssassin rule test, NJABL (agregate) matched 57.6% of their
spam, and 3.6% of their nonspam messages in the test.. Not bad, but there
will still be a significant portion of spam that gets around it.