ietf-smtp
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Re: port number for smtp over ssl

2003-01-15 10:47:15

On Wed, 15 Jan 2003 09:14:18 -0800
Dave Crocker <dhc(_at_)dcrocker(_dot_)net> wrote:


Folks,

The 'alternate' port used for doing SMTP over SSL is 465. This appears
to be a well-established, de facto standard.

Alternate port numbers are a bad idea, especially when implementations
try to do opportunistic encryption (as many do) by switching from one
port to another.  There is an SMTP extension allowing negotiation of
TLS-over-SMTP in RFC 3207.  This is what implementations should be
using.

--
Keith Moore                              http://www.cs.utk.edu/~moore/
27 February 1933                                     11 September 2001