Security Incidents mailing list archives

Re: Massive SPAM Increase {-2.6} {-2.6}


From: Brent Kearney <brent () kearneys ca>
Date: Mon, 9 Oct 2006 16:28:24 -0600


On Oct 9, 2006, at 15:29, Tim wrote:

Its purpose is to reject *all* mail from bogus MTAs - dialups,
misconifigured servers, MTAs that aren't registered in the domains' DNS as a "legal" MX, MTAs that don't reverse properly, etc., etc. If the email is
forged in any way, it will never make it to DATA.

That's great, except it makes the internet more expensive for the little guy. If you're trying to run a non-spamming personal mailserver off of
a consumer DSL or cable line, you can get screwed by others' policies
like this because you may not have control over your PTR records or how
your ISP lists you as a non-MTA with other organizations.

Some university campuses maintain strict control over their reverse DNS entries, and so departments or on-campus organizations, research institutes, etc. that run their own mail servers will have non- matching forward and reverse DNS entries on their MX hosts. Blocking rules like this make life difficult for them as well.

Cases such as these raise the question, if the blocked mail never gets into your network, how would you know about the rate of false- positives?

Brent



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