iRedMail might be a bit more popular than OpenSMTPD. We know about 2 links to it since March 2021 and only 2 links to OpenSMTPD. 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.
I've had something of the same experience with Postfix, u/0x29aNull. Check out OpenSMTPD. It is lightweight and standards compliant. I know that there are packages for Debian and Alpine Linux. There may also be ones for Fedora/RHEL derivatives. I use it in my environment on OpenBSD. Source: about 1 year ago
When I installed Rspamd with on OpenBSD / OpenSMTPD the other day, DKIMProxy out (dkimproxy_out daemon), which had been got via OpenBSD Ports package system, was used to add DKIM signatures to mails in order to improve security on emails. - Source: dev.to / almost 3 years ago
For photo I use Immich. For contact and calendar I use my own mail server (iRedMail). For Cloud I have my own nextcloud server. With nextcloud you can sync contact and calendar of uou don't have a mail server likes iRedMail. Source: 10 months ago
I used to spend all my time maintaining e-mail quirks for my server. Adjust this, updated that, fix this breakage, yada yada. But then I decided to setup iRedMail which uses postfix, dovecot, certbot, roundcube, spamassasin, mariadb, ldap and all the bells and whistles. All I have to do now is make sure I don’t break it doing any software upgrades on freebsd. 10/10 scores after configuring and blacklist free. Source: about 2 years ago
Postfix - Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail.
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.
sSMTP - sSMTP is a simple MTA to deliver mail from a computer to a mail server.
mailcow - An open source mailserver suite.
Exim - Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet.
Roundcube - Web-based IMAP email client