[78241] in North American Network Operators' Group
Re: Why do so few mail providers support Port 587?
daemon@ATHENA.MIT.EDU (Eric A. Hall)
Fri Feb 25 12:08:13 2005
Date: Fri, 25 Feb 2005 12:03:14 -0500
From: "Eric A. Hall" <ehall@ehsco.com>
Cc: nanog@merit.edu
In-Reply-To: <20050225105155.B11227@torzimon.ca.int.kn>
Errors-To: owner-nanog@merit.edu
On 2/25/2005 10:51 AM, Nils Ketelsen wrote:
> On Thu, Feb 24, 2005 at 11:36:40PM -0500, Valdis.Kletnieks@vt.edu wrote:
> I force anyone, who wants to relay to use SMTP-AUTH on port 25. Only mails
> for local delivery are accepted without AUTH. Whats point
> in opening another port?
There are lots of secondary benefits. One of my favorites is that I can
reject mail session on port 25 from hosts that claim to be in my domain
(all such mail is authenticated on port 587 or is coming from a
pre-configured list of servers that already hit an exception, so any other
connections on port 25 that HELO as ehsco.com are lying). There are lots
of these kinds of non-trivial benefits.
--
Eric A. Hall http://www.ehsco.com/
Internet Core Protocols http://www.oreilly.com/catalog/coreprot/
