On 02/24/2011 06:44 AM, Ian Eiloart wrote:
It's absolutely normal, and even recommended, to set up SMTP access for
clients on port 587 provided that you must require authentication for
connections on that port. It's quite likely that your SMTP server supports
authenticated connections on port 587.
The service (SMTP on port 587) is called Message Submission Agent, and is
required to bypass the blocks that many ISPs put on direct connections on
port 25.
If I had my way here at UC Davis, our mail servers would be thus:
smtp.ucdavis.edu: port 587 (only)
mx.ucdavis.edu: port 25 (only)
Alas, the legacy of previous decade practice means I have to
allow port 25 on my SMTP pool systems. For on-campus
we allow relaying on that port, for off-campus you must
authenticate.