iRedMail is open source mail server on Linux server. iRedMail gives numerous features, for example, it is totally safe and secure as the entirety of its components is open source. Your security is totally ensured as the application and data are stored on your own hard drive. The best part of iRedMail is that it provides a web-based admin panel from where admins can do all the email related operations task like managing users. Some of the other features are listed below: Support unlimited email accounts.
It provides Roundcube Webmail default MUA
It used Postfix as an SMTP service (MTA)
It used Dovecot as POP3/POP3S, IMAP/IMAPS service (MDA)
An interface between Postfix and SpamAssassin, ClamAV. Used for spam and virus scanning.
OpenLDAP, MariaDB, and PostgreSQL can be used to save mail accounts
Fail2ban scans log files /var/log/maillog file and bans IPs that show malicious system attempts.