I came across some software today that’s been around a while, but seems to have been flying under the radar. It is called Xeams and it is a SMTP/Email server for Windows operating systems. It can act as a Full Email server, Spam Firewall or both.
Since Microsoft seem to have stealthily removed event sinks in IIS, they no longer seem to work in the SMTP that comes with IIS7 on Windows 2008. So I’m using Xeams to filter email notifications coming from a bespoke application that sends out way too many emails. It has some extensive spam and mail filtering capabilities, better than in some paid products you typically see around in the enterprise. Very useful and completely free! They make their money from support contracts if you are using it heavily and require professional support.