On Dec 21 2004, Barry Shein wrote:
It's difficult to measure what you block.
I think it's enough to discuss actual messages accepted for delivery or
filtering by the SMTP servers. See below.
I will say that another huge part of the problem is the stuff no one
ever sees which is the bazillions of user unknowns as the spammers use
various dictionary type attacks. There's far more user unknown
attempted deliveries than other deliveries.
The dictionary attacks use up incoming bandwidth, and processing or
storage.
Without knowing the numbers, it's hard to know if the bandwidth used
is a large fraction of incoming capacity, but I doubt it.
However, the processing involved is in principle fully scalable.
There's only the need to exchange a request which can be denied by the
SMTP server for nonexistent users. So the full email is only
transmitted if the mail is accepted.
Figuring out whether a recipient address represents a real user is a
fast operation in principle, ie no matter how many valid user
addresses, a yes/no needs O(1) operations with the right algorithms.
So from a scalability POV, I'd expect the costs of spam to be mainly
proportional to those messages which are sent to a valid user.
So, even if you knew what went (or would go) into peoples' mailboxes,
opening the floodgates (AKA accepting EFF's point of view) would also
necessitate sifting through all that spew, increasing costs
significantly.
Interestingly, Google started this fad of offering 1 gigabyte
mailboxes. I don't know if they crunched the numbers and figured it's
economically worthwhile, or whether they just have IPO money to burn.
--
Laird Breyer.
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