That's kind of neat: September 2021

Thursday, September 30, 2021

Cuttlefish (not a mail server, but an open source alternative to transactional mail services like Mailgun and Sendgrid).

Postal is another product like Cuttlefish

Omeka is an Open-source web publishing platforms for sharing digital collections and creating media-rich online exhibits

There are more out there than I thought. All of these are free and current as of this post.

ASSP, Anti-Spam SMTP Proxy Server

EFA Project, Email Firewall Appliance Project

Mailscanner, with a web front end called MailWatch

Spamassassin, from the Apache Foundation

Web interface for the dig command.