Why do so few mail providers support Port 587?

Wed Feb 16 02:16:55 UTC 2005

On Tue, Feb 15, 2005 at 09:00:11PM -0500, Sean Donelan wrote:
> 
> Sendmail now includes Port 587, although some people disagree how
> its done.  But Exchange and other mail servers are still difficult
> for system administrators to configure Port 587 (if it doesn't say
> click here for Port 587 during the Windows installer, its too
> complicated).

This is utterly silly.  Running another full-access copy of the MTA
on a different port than 25 achieves precisely nothing -- and this
"support" has always been included in sendmail, with a 1-line change
either to the source code (long ago) or the default configuration or
simply by running sendmail from inetd.

What benefit, exactly, do you see to allowing unauthenticated mail
submission on a different port than the default SMTP port?

Similarly, what harm, exactly, do you see to allowing authenticated
mail submission on port 25?

What will actually give us some progress on spam and on usability
issues is requiring authentication for mail submission.  Which TCP
port is used for the service matters basically not at all.

Thor