Postfix

But lower volume, and maybe you don't want to be paying for that service, there's still options for doing it on-premise, whether that's for a copier or for a line of business app like this scenario.

And so we're helping them set up Postfix, but also navigating.

There are some variables if you're going to send it through Microsoft.

You've got to use the right encryption, the right ports, make sure SPF and DKIM are also aligned because those will still be enforced on that.

Subscription requests went to python-list-request@cey.nl. That dash request convention survives in mailing list software to this day.

A thirty-five-year-old naming convention still sitting in Postfix config somewhere.

Everywhere.

And there's an earlier breadcrumb.

You need to audit your outbound TCP port 25 connections, but you have to look contextually.

Specifically, hunt for port 25 traffic originating from processes that are not your actual authorized mail transfer agents like Postfix or Exim.

Got it.

If a process named Oramon is suddenly routing SMTP traffic to the internet, you have a critical compromise on your hands.