Re: Email direct from IBM i without relay (was: New lower cost IBMi announced)

Not exactly correct, Nathan.

On Thu, Feb 16, 2017 at 4:00 PM, Nathan Andelin <nandelin@xxxxxxxxx> wrote:

The subject of how email works, and especially the jargon can be confusing.
I'll delineate a few basics and let others fill in with more detail. Say
you want to send an email to:

john@xxxxxxxxxxx

Setting all formatting aside (for the moment, in order to focus on
communication), a program or services needs to use a TCP socket to connect
to the SMTP server on port 25 at example.com, send the message, then
disconnect. IBM i has an SMTP client that can do that for you.

Actually the email client normally connects to a mail router (which can be
an in house exchange server, a cloud based server like gmail or office365,
your ISP's mail router, etc) and drops the mail off there. Then the mail
router delivers to the final recipient (at example.com).

In 99.9% of the cases, this is how it works with PC clients or clients such
as SNDDST, MSF, MAILTOOL, ESEND, etc.

I won't get into why (except reverse DNS being one) but rarely if ever
should email be delivered directly from the client to the recipient.

Although, I've seen things setup to deliver directly more than once and
usually when they contact me asking why it doesn't deliver to specific
domains. Again, you're right that there is confusion with how email works.

Port 25 is only for non-secure connections. 465, 587 and others are used
for SSL/TLS. When connecting to a mail router that requires that type of
authentication.

Bradley V. Stone
www.bvstools.com
Native IBM i e-Mail solutions for Microsoft Office 365, Gmail, or any Cloud
Provider!