iRedMail is a full-featured mail server solution: https://www.iredmail.org/

Don't forget to check out our lightweight email archiving software: https://spiderd.io/

It supports few mainstream Linux/BSD distributions:

• CentOS Steam 8, 9
  • Note: CentOS 7 and 8 are not supported, please use CentOS Stream or Rocky Linux instead.
• Rocky Linux 8, 9
• AlmaLinux 8, 9
• Red Hat Enterprise Linux 8, 9
• Debian 11
• Ubuntu 22.04 (Recommend), 20.04
• FreeBSD 13.x
• OpenBSD 7.3

More info:

• License: GPL v3
• Authors: Zhang Huangbin (zhb at iredmail.org)
• Check and download the latest stable release from website
• Install iRedMail by following our installation guides strictly: Installation Guides
• Community, bug report, feature requests: online support forum
• We offer paid support services
• Source packages patched or modified for RHEL/CentOS can be found here, other RPM packages are all installed from official yum repository and EPEL.

We recommend to deploy iRedMail server with the iRedMail Easy platform, it offers easy deployment, one-click upgrade, and tech support via the ticket system. Check our website for more details.

There's also an all-in-one Docker edition here: iredmail/dockerized.