We've announced some changes our policies on Simple Network Management Protocol (SNMP) and Simple Mail Transport Protocol (SMTP), which will affect a very small portion of our customers. You can find more information in two blog posts. One is a general post about both issues, and the other is specific to SMTP. While the policy change was announced today, implementation will occur gradually.
Changing my Outlook settings for outgoing to use port 465 with ssl. Tests were ok, now going live on my main email account. I'll post results later in the day.
"Once I talked to the inmates of an insane asylum in Hartford. I have talked to idiots a thousand times, but only once to the insane..." Mark Twain
The blog mistakenly claims that port 587 doesn't offer SSL encryption. The difference between 465 and 587 is that 465 is encrypted by default, but port 587 can use the STARTTLS command to switch to encrypted mode. So as long as you check the appropriate box in your client settings to use SSL or TLS, it doesn't matter which port you use.
My understanding is that 465 has never been an officially blessed port, it was something Microsoft came up with (maybe before STARTTLS was added to the SMTP protocol).
I've heard a number of stories on where 465 came from, but you'll notice wider adoption across major email providers over the last year or so. Comcast has supported 465 for more than 5 years now. We agree with the adoption of the "by default" security that 465 provides.
