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.
Postfix - Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail.
Google Workspace - Google's encompassing suite of cloud-based business apps.
sSMTP - sSMTP is a simple MTA to deliver mail from a computer to a mail server.
Microsoft Exchange Server - Microsoft Exchange Server is a messaging and collaborative software product developed by Microsoft.
Sendmail - Sendmail is a general purpose internetwork email routing facility that supports many kinds of...