-----Original Message-----
From: asrg-admin(_at_)ietf(_dot_)org [mailto:asrg-admin(_at_)ietf(_dot_)org]On
Behalf Of Scott
Nelson
Sent: 09 May 2003 17:17
To: Asrg(_at_)ietf(_dot_)org
Subject: Re: Fwd: [Asrg] How many legitimate SMTP servers?
At 08:37 PM 5/8/03 -0400, Yakov Shafranovich wrote:
From: "Ken Hirsch" <kenhirsch(_at_)myself(_dot_)com>
Does anybody have an idea of how many legitimate SMTP servers there are?
That is SMTP servers that are not used primarily for spam, have a static
IP
address, and have been active in the last, say, 12 months.
These might be a starting point:
http://cr.yp.to/surveys.html
http://www.isc.org/ds/
From the first link, I see that on 2001-10-03,
D. J. Bernstein estimates over 4 million
(estimate made from a sample of 1 million random IPs)
42% ran some flavor of sendmail,
17% ran Microsoft Exchange or IIS.
17% ran qmail
(there were others, see the original survey)
His methodology looks good, I trust these numbers were reasonably
accurate in 2001-10-03. That was over 18 months ago,
a long time in internet years, but I think they probably haven't
changed all that much since then.
Scott Nelson <scott(_at_)spamwolf(_dot_)com>
-----------------------------------------------------
I think "probably haven't changed all that much" is a bit suspect. We can
expect the trends reported by DB to have continued. So for example if the
decline in sendmail continued over the last 18 months as it had over the
previous couple of tears we should expect it to represent maybe 35% now.
The proportion of hosts that respond on port 45 had increased - why
shouldn't it have increased again? The hostcount reports (for example those
from RIPE) indicate a considerable increase in the number of hosts over the
18 months since DB's last survey (continuing a long-standing trend) so we
might expect to see something over 5 million SMTP servers instead of
something over 4 million.
Of course we then have a second problem: DB's figures are for servers which
receive mail on port 25, while the original query was for servers that
transmit mail on port 25. These are not the same servers so the numbers may
not be right (far more transmit than receive, I think).
Tom
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