Authenticated SMTP
From SWCP Support Wiki
Mre and more networks around the world are placing restrictions on who can send email through their services, and how they may do it. Sadly, this is a necessary step in the ongoing battle against spammers. Many of our customers need to send mail through the SWCP mail servers while using non-SWCP network connections (at a hotel, in a coffee shop, on a Comcast connection, etc.) The way to do that is using Authenticated SMTP.
Authenticated SMTP is a method for your email software to tell our mail server who you are, using your username and password. It is supported by all modern email software and is easy to set up. If you have had your email rejected for any of the following reasons, this will usually fix the problem:
- PBL rejection
- SPF rejection
- Port 25 blocked
