SmartPost mail software is originally based on UNIX operating system. But it can be implemented on any operating system that supports all the parts of SmartPost.
The core of the system is MySQL server that holds the database of all users accounts.
SMTP server (MTA-mail transfer agent), POP and IMAP servers get users account info from database.
Thus we do not need to add any UNIX users to /etc/passwd file.
Mail is stored in maildir format.
The primary advantage of maildirs is that multiple applications can access the same Maildir simultaneously without requiring any kind of locking whatsoever. It is a faster and more efficient way to store mail.
The system is protected by UNIX kernel internal firewall system.
The diagram below shows the processes "behind the scene".
- UNIX Operating System
Any UNIX/Linux operating system that supports XMail MTA, MySQL, PHP and Courier-IMAP.
I based my installations on
Linux RedHAT 9 (www.redhat.com)
- SMTP server (Mail Transfer Agent MTA)
XMail is an Internet and Intranet mail server featuring an SMTP server, POP3 server, multiple domains, no need for users to have a real system account, SMTP relay checking, RBL/RSS/ORBS/DUL and custom (IP based and address based) spam protection, SMTP authentication (PLAIN LOGIN CRAM-MD5 POP3-before-SMTP and custom), a POP3 account synchronizer with external POP3 accounts, account aliases, domain aliases, custom mail processing, direct mail files delivery, custom mail filters, mailing lists, remote administration, custom mail exchangers, logging, and multi-platform code.
- IMAP server
Courier IMAP + authmysql. (www.courier-mta.org)
Courier-IMAP is a server that provides IMAP access to Maildirs. It was written for the specific purpose of providing IMAP access to Maildirs.
- SQL database server
MySQL database management system (www.mysql.com)
- Web server
Apache + PHP (www.apache.org)
PHP Hypertext Preprocessor (www.php.net) is an HTML-embedded scripting language.
- SmartPost web-based mail access tool and administration tool
SmartPost is the key software here.