[Greylist-users] Too many "false positives" !?!
jim at wrightthisway.com
Sun Nov 20 14:32:38 PST 2005
On Nov 20, 2005, at 6:35 AM, orinoco wrote:
> Within two days I got so many "false positives", 1st rejected by
> greylisting and then the remote MTA does not retry to deliver the mail
> for hours, for days ... even major providers like web.de do only try
> once and then generate a delivery error.
One would think that a major provider would not operate broken
servers, but this isn't always the case. There are a good many
reasons for a message to be temporarily undeliverable, and dropping a
message on the first bad attempt is just bad business, not to mention
a violation of RFC standards.
> That does not correspond with the promises on several wesbites
> almost no false positives from greylisting. Didn't they counter-check?
> Are there so many non-RFC-compliant MTAs out there? Or what's going
> wrong here?
I normally watch my logs closely, and attempt to contact any server
owners that have misconfigured servers, there are a lot of folks out
there that just don't know any better, and have no clue what they are
doing. A little education can go a long way. I usually copy
whatever contacts I can find for a particular domain, including what
IT contacts I can find. I also let the customer who's mail was
rejected know that they're using a poorly configured service, just so
they know who's fault the problems are.
> It's an underdog job to check for false positives, not to mention
> repairing the communication damage.
> And I can't whitelist all innocent non-RFC-comnpliant MTAs on the
There are several good whitelists out there as a starting point, in
my experience most of the bad servers are ones I don't need to
receive mail from anyway.
> Additionally some web-mail providers like hotmail hide the greylisting
> error message from their customers, generating a delivery failure
> message of their own, if they notify at all.
I've never had an issue greylisting Hotmail mails. Their servers do
seem to retry normally.
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