Dragonfly Mail Agent might be a bit more popular than Postfix. We know about 1 link to it since March 2021 and only 1 link to Postfix. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Read the documentation on postfix.org and/or buy one of the many available Postfix books (it really helps to understand the Postfix philosophy). Source: about 3 years ago
I've been using dma, see if it suits you. Https://github.com/corecode/dma. Source: over 2 years ago
iRedMail - A fully fledged, free email server solution, an open source project (GPL v2).
OpenSMTPD - OpenSMTPD is a FREE implementation of the server-side SMTP protocol as defined by RFC 5321, with...
Zimbra - Zimbra is trusted by over 500 million users to increase productivity with a complete set of collaboration tools while maintaining total control over security and privacy.
Exim - Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet.
sSMTP - sSMTP is a simple MTA to deliver mail from a computer to a mail server.
mailcow - An open source mailserver suite.