Mail Submission Protocol
dot at dotat.at
Thu Apr 22 06:07:49 CDT 2010
On 22 Apr 2010, at 00:07, Franck Martin <franck at genius.com> wrote:
> Consider also smtps port which should be treated like smtp port and
> not like submission port, or simply do not listen on smtps as TLS is
> available on smtp port via esmtp.
Er, no. TLS-on-connect aka smtps (as opposed to STARTTLS) is only used
to support Microsoft MUAs that are more than a couple of years old.
They only supported STARTTLS on port 25 and insisted on using the
deprecated TLS-on-connect mode on all other ports. This meant they
could not support standard Message Submission on port 587. Therefore
you should treat smtps (TLS-on-connect on port 465) as the special
Microsoft version of RFC 4409 message submission. That is, treat the
protocols exactly the same wrt authentication, authorization,
firewalls, address validation, etc.
f.anthony.n.finch <dot at dotat.at> http://dotat.at/
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