pgl4rbl implements a Postfix policy server that mixes two widely used techniques: greylisting and RBL (DNS blacklists). The idea is that greylisting is applied only to SMTP clients that match a RBL; this means that normal clients are not delayed (such as with a normal greylisting implementation), and RBL false positives do not cause problems (like when outright blocking them at the SMTP level).
ChildProt is a child protection policy daemon for Postfix. It checks a list of recipient addresses. If the current recipient address is found, the sender address is verified against a whitelist. If the current sender address is found, the mail will be delivered to the recipient. If the sender address is not found on the whitelist, the mail will be redirected to a delegate of the recipient. If the recipient address is not found the mail will be delivered to the recipient too.
POP-Before-SMTP-Auth is a POP before SMTP daemon for Dovecot and Postfix that works by scanning mail server log files. The line-matching regex can be changed from the configuration file, in case Dovecot's logging format changes, and also to adapt the script for use with something besides Dovecot. Presently the script requires that the IP address appear on a single line with the successful login in the log file.
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).
vmm is an easy-to-use and configurable commandline tool for administrators and postmasters, used to manage domains, alias-domains, accounts, and relocated mail users. It allows fast and easy management of mail servers. It's designed for installations using Dovecot and Postfix with a PostgreSQL backend.