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more on Verizon Discovers The Cost Of Being Too Aggressive In Blocking Spam]
From: David Farber <dave () farber net>
Date: Wed, 5 Apr 2006 08:32:22 -0400

Begin forwarded message:

From: John Levine <johnl () iecc com>
Date: April 4, 2006 7:26:32 PM EDT
To: Lee Revell <rlrevell () joe-job com>
Cc: dave () farber net
Subject: Re: [IP] more on Verizon Discovers The Cost Of Being Too Aggressive In Blocking Spam]

"In late 2004 Verizon implemented a massive blocklist for DSL
customers, that seemed to block a ton of email from outside the
country -- with no way to get around the list.

What a terrible precedent.  No good deed goes unpunished.

This kind of thing was commonplace and necessary before spam filtering
became sophisticated.

It may have seemed that way in your corner of the net, but it was and
is neither.  Verizon has a long history of using spam filtering
techniques that are clumsier and more intrusive than other ISPs,
notably callbacks that simulate sending mail back to a nominal sender
to check if the address on incoming mail is real.  (This, of course,
means, that if someone sends Verizon a spam run with your address
faked as the return, Verizon will mailbomb you.)

As far as I can tell, some whiz at Verizon tried to make a list of all
of the foreign IP addresses that sent mail to their customers, then
blocked everything else.  It should have taken about two minutes for
it to become clear that the whitelist was missing a lot of entries,
but Verizon, being The Phone Company and therefore infallible,
stonewalled and made absurd excuses rather than saying oops and
backing it out.

So although I entirely agree that it is counterproductive to penalize
people for good-faith spam filtering mistakes, in this case, Verizon
had it coming, and I hope they've learned to be more careful.

John Levine, johnl () iecc com, Primary Perpetrator of "The Internet for Dummies",
Information Superhighwayman wanna-be, http://www.johnlevine.com, Mayor
"More Wiener schnitzel, please", said Tom, revealingly.

PS: I happen to run a country blacklist called korea.services.net
which I use to block mail from most Korean ISPs.  But that's because I
have a small user base, I know my users, and few of them have
correspondents in Korea.  It would be nuts for an ISP to use it.

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