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Re: [Asrg] C/R Interworking Framework

2003-06-04 19:54:17
At 06:01 PM 6/4/2003 -0600, Vernon Schryver wrote:

> From: Yakov Shafranovich <research(_at_)solidmatrix(_dot_)com>

> ...
> However, if we are defining an SMTP process for CRI protocols, can we use
> the VRFY command as a part of an ESMTP extension?

What about deployment and adoption rates?  Do you want it to work
even with MTAs not running your new protocol?
In other words, do you want it to work only in theory or to also have a
glimmer of a hope of working in the real Internet within the next 20 years?

As I pointed out before in a posting to Eric Dean, my vision is a multi-stage CRI protocol. The basic protocol would use RFC 2822 headers and human-readable email, which would be compatible with current MTAs. As C/R systems become more common, they can negotiate to use the other parts of the protocol such as an ESMTP extension or MIME fields. An extension mechanism would be in place where the protocol can be extended to support things like PKI, hash cash, etc. The VRFY command would be part of that ESMTP extension which will be used by C/R systems that want to, and not used by existing MTAs. Existing MTAs will start off by supporting the basic protocol or if they want the other parts.

Additionally, deployment and adoption rates is something that should be considered in more detail (this would be something that Eric Brunner can help us with). According to D. J. Berstein's SMTP statistics (http://cr.yp.to/surveys/smtpsoftware6.txt), the following breakdown of major MTAs was present on the Internet in 2001 (out of 958):

401/958 41.85%          UNIX Sendmail
176/958 18.37%          Windows Microsoft Exchange or IIS SMTP
167/958 17.43%  UNIX qmail
57/958  5.9%            Windows Ipswitch IMail

These four accounted for about 84% of all MTAs with the other MTAs were 1% or less. Of these, qmail and sendmail account for 59.28% of all MTAs, with the Windows ones accounting for the other 24.27%.

IF a CRI protocol is implemented and both qmail and sendmail support it, that would mean that a sizable majority of the Internet would support it. If Microsoft jumps in, that would increase the effect. The question remains, taking the impact of qmail and sendmail, and the propagation rates for admins installing the newest versions, how long would deployment take?

Yakov




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