This howto describes one way to build a scalable, secure, full-featured mail platform. It offers virtual hosting of mailboxes in maildir format with support for quotas and server-side filtering, domain aliasing, address aliasing, address forwarding, catchall addresses. Relaying is secured with STARTTLS and SMTP-AUTH. Incoming mails are checked for viruses, spam, and checked against SPF policy and DNSBL.