[95776] in North American Network Operators' Group
Re: Blocking mail from bad places
daemon@ATHENA.MIT.EDU (Thomas Leavitt)
Tue Apr 3 13:22:42 2007
Date: Tue, 03 Apr 2007 10:19:47 -0700
From: Thomas Leavitt <thomas@thomasleavitt.org>
To: michael.dillon@bt.com
Cc: nanog@merit.edu
In-Reply-To: <D03E4899F2FB3D4C8464E8C76B3B68B0205ED3@E03MVC4-UKBR.domain1.systemhost.net>
Errors-To: owner-nanog@merit.edu
The only practical way to handle the volume of spam email that was
hitting my servers was to implement very very aggressive filtering at
the server accept level (requiring valid HELO commands that match to an
existing host, among other things - amazing how many servers from major
sites that initiate a HELO using a non-existent hostname)... and a
friend of mine who manages a whole series of servers, has taken it to
the next level: he implements his spam blocking via firewall (the
disadvantage is that the logging is much more sparse, and the error
messages much less descriptive).
The alternative is the absurdity that a local ISP has: a 14 way cluster
for mail acceptance, and another 20 way cluster for mail storage and
retrieval with terabytes of storage space, 90% of the resources (or
more) of which are taken up accepting and storing as much spam as
possible... and this is an ISP with a few thousand dial up and DSL
customers, and a small datacenter with three rows of racks. ... and none
of these resource usages are billed back to the customers... they're
just overhead.
The current situation with email is flat out insane. There is no other
way to describe it.
Email quaint? You betcha - my kids and their friends do "email" all the
time: via MySpace and the equivalents, no SMTP required. They wouldn't
know what an email client was if you hit them over the head with it.
Thomas
michael.dillon@bt.com wrote:
>
>
>> You cannot mandate how hard somebody must work. It doesn't work. Make
>>
> it
>
>> 'expensive enough' to be wrong, and *then* they will make the
>>
> necessary effort
>
>> to be 'right'.
>>
>
> Some people block mail from bad places in an attempt to hurt the bad
> place, i.e. in an etempt to make it expensive for them to be bad. But
> nowadays there are so many bad places, so much SPAM that leaks through
> filters, and so many missing emails, that it becomes harder and harder
> to hurt the bad places by blocking email. Nowadays it is normal for
> email to mysteriously bounce, to go missing, to get delivered days or
> months late. Soon Internet email will be like IRC, a quaint service for
> Internet enthusiasts and oldtimers, but not a useful tool for businesses
> or ordinary individuals.
>
> --Michael Dillon
>