Why do so few mail providers support Port 587?

Fri Feb 25 17:08:45 UTC 2005

On 2/25/2005 11:17 AM, andrew2 at one.net wrote:

> department.  I'll agree with you on one thing, though -- the whole
> business of port 587 is a bit silly overall...why can't the same
> authentication schemes being bandied about for 587 be applied to 25,
> thus negating the need for another port just for mail injection?

It's not just authentication. Mail from local users might need some fix-up
work done to it, like adding Date or Message-ID, or completing a
mail-domain in an address, or doing some other kind of cleanup. You don't
necesarily want to do that for server-server messages, since their absence
is good spam-sign, but at the same time you do want to do it for user
mail. You can also conduct different kinds of tests, perform different
kinds of rate-limiting, map in different headers (auth, for example), and
so forth.

Separating your traffic is good management.

-- 
Eric A. Hall                                        http://www.ehsco.com/
Internet Core Protocols          http://www.oreilly.com/catalog/coreprot/