We want to use email relaying for our outgoing mails, to avoid email spoofing - aka
From the official documentation I learned to use an unsecured SMTP server to do so. I asked Salesforce support and they confirmed it. My mail provider barked at me: Unsecure SMTP? That'd be an open invitation to spammers! Of course they would not do it. There is also an Salesforce Idea entry describing the same problem, with no obvious answer.
We've been using Mail to Salesforce and Cirrus to get somewhere near native mail support, but we really need to be able to send mails from within Salesforce. We need templating and the ability to onboard sales persons who only work within Salesforce.
How can we do it - without an open SMTP? How are you doing it? How are really big companies doing it?