[95817] in North American Network Operators' Group
Re: Blocking mail from bad places
daemon@ATHENA.MIT.EDU (John Levine)
Wed Apr 4 15:44:18 2007
Date: 4 Apr 2007 19:43:24 -0000
From: John Levine <johnl@iecc.com>
To: nanog@nanog.org
In-Reply-To: <4613EBF1.3090701@peter-dambier.de>
Cc: peter@peter-dambier.de
Errors-To: owner-nanog@merit.edu
>> While its a pretty brute force approach, one method I’m trying is to
>> curtail the source of email. In otherwords, if smtp traffic comes from an
>> unknown source it gets directed to a sendmail server that intentionally
>> rejects the email message (550 with a informational message/url).
> 1) You send bounces from spammers to innocent people, whose
> addresses have been forged.
This is an SMTP reject, not a bounce. It's a lethal variety of
greylisting.
This technique works great to keep spam out of your mailbox.
>3) You are dropping valid emails.
Right. It also quite an effective way to be sure you never hear from
non-technical users who don't understand your bounce message, and from
people like me who don't feel like jumping through your hoops,
particularly in a case like this where we're responding to a question
you asked.
R's,
John
