nanog mailing list archives

Re: Response from Cyber Promotions (fwd)


From: Taner Halicioglu <taner () isi net>
Date: Mon, 21 Apr 1997 10:37:31 -0700 (PDT)

On Mon, 21 Apr 1997, Doug McIntyre wrote:

But most of the bulk spammer programs out there don't follow MX
records. They blast directly into the sendmail port of the primary
machine, and if they can't do that, they leave it at that and move
on.. Blocking spam sites directly at the sendmail level (with
tcp_wrappers), does effectively block out bad domains. 

You sure about not following MX'?  There is a machine, 'isi.net', but it
doesn't accept mail, and there's an MX pointing to out real mail machine,
yet we constantly get spam :-)

Otherwise everyone would've used this trick to avoid spam :)

Some of the sendmail rules listed at http://spam.abuse.net/spam/, like the
one that forces the MAIL FROM line to actually resolve, would probably
block a lot of spam, too.  But I was wondering if this requires the
address to have an A record, or will an MX suffice;  I know lots of people
that send as "user () domain com" where domain.com is an MX only...  I'm just
not familiar enough with sendmail rules to know how it works ;-)

If Cyberpromo were really trying to *cough* help, they would set all the
reply-to's in the spams to "abuse () cyberpromo com"  ;-)

yeah... right...

        -Taner
--
      D. Taner Halicioglu                     taner () isi net
  Programmer/Engineer/Sysadmin            Internet Systems, Inc.
    Voice: +1 408 543 0313                 Fax: +1 408 541 9878
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