Clement is an email server application. Its main function is to block unwanted mail (spam) as soon as possible in the email exchange process. It accepts or rejects email while the SMTP session, initiated by the email sender, is still pending, accepting legitimate email messages without the need to return an error status to non-existent or "borrowed" return address later. Clement can operate in two modes, either as a standard MTA (as sendmail, Postfix, Exim, Exchange, etc.) to store email in the recipient's own area, or to transmit the mail to an another SMTP server acting as smart spam filtering device. Each email domain name Clement knows about can be treated in one of these two modes depending on the group to which the domain name has been set. Each message is verified by a virus scanner (ClamAV) while the SMTP connection is still open, but the refusal of mail and the reason for refusal is notified to the actual sender. Mail management is done via a Web interface and can be delegated to three administrative levels (Root-Admin, Group-Admin, Domain-Admin). Standard users can access their own logs (sent email status, email rejected, quarantined email, etc.). With this interface, the user can handle the rejection and acceptance of mail. Users who are level "Admin" can access the session logs (via the Web interface). Clement uses a SQL database (PostgreSQL, MySQL) to store and manage logs, user profiles, and dynamic management of directives concerning the sender-receiver relationship.
Masqmail is an MTA (mail transport agent) for notebooks, workstations, home servers, and generally any host with no permanent network connection. It has special support for multiple transfer routes (e.g. to different mail providers). Address rewriting can be done in several ways. It is a slim replacement for full-blown MTAs such as sendmail, exim, qmail, or postfix and for the intended uses, configuration is much simpler.
Why a milter archiver? If you are required to also log source and destination IPs and BCCs (additional rcpt to's not in a CC field communicated at the SMTP protocol level), then the only option is do this in the MTA, or in a milter application that has hooks in the MTA process (which is exactly why milter was invented). It uses a simple regex file that can be used with several *source target-mailbox rules to define what gets mirrored where. The archiver tries to be as quiet as possible. The possible methods to archive are SMTP, sendmail inject / Postfix inject, IMAP delivery, and milter-add recipient. It was build as a replacement for a Postfix BCC setup: (sender_bcc_maps = regexp:/etc/postfix/archive; recipient_bcc_maps = regexp:/etc/postfix/archive).
Yasma (Yet Another Sendmail Logfile Analyzer) is a reporting tool for sendmail log files. It provides a nice overview of your mail traffic like: messages transferred, some average values, top lists of messages sent, received, rejected, etc., and top lists of supposed spammers, status messages, relay hosts, and mailers. It analyzes one or more log files from the command line and writes an HTML report. For security, it can hide the user part of mail addresses listed in the report. A GeoIP database can be used to show country information.