On Wed, Nov 12, 2008 at 11:33:46AM -0800, Randy Presuhn wrote:
> Huh? Concrete, real example: I send a message to an IETF mailing list.
> A list subscriber's ISP rejects the forwarded message. IETF's mailman
> drops the subscriber, because this has been happened multiple times.
> I can't notify the subscriber, because their ISP also rejects my email.
This is not a DNSBL problem. This is a problem with the subscriber's ISP,
which is not operating their mail system per de facto best practices --
which include making sure that rejection notices provide an alternate-channel
means of contacting them in order to discuss apparently-erroneous blocking.
There are a sizable number of techniques for doing this; I happen to think
the best ones are quite simple, e.g.:
reject=550 5.7.1 <[EMAIL PROTECTED]>... Mail refused - [201.45.252.2]
listed by Spamhaus (http://www.spamhaus.org) - forward this message to [EMAIL
PROTECTED] if you believe this is a mistake
of course [EMAIL PROTECTED] needs to be exempted from the same
blocking and should forward to the postmaster/abuse staff at example.com.
There are many other ways to accomplish the same thing at minimal effort
and cost; the unifying factor they all share is that recognize that all
anti-spam setups have non-zero FP rates, so it's a good idea to be prepared
to deal with those situations when they arise.
---Rsk
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