qmail-ldap is an extension to stock qmail-1.03 to get all user account information from an LDAP database. Its primary target is POP toasters with thousands to millions of users, such as in ISP, FreeMail, and Corporate environments. It features full SMTP/POP3/IMAP server clustering for scaling and high availablity. Additionally there are state-of-the art spam filters, TLS SMTP encrytion, and mailbox quotas. A migration path for Netscape Messenger and Software.com's Post.Office installations is provided.
stdnoj is a cross-platform C++ class library that includes classes for using portable strings, databases, SMTP, POP, NNTP, arrays, files, directories, logging, email, and sockets. While templates are used, no reliance upon STL or other (traditionally error-prone) technologies has been used, which increases portability between compilers.
tpop3d is yet another POP3 server. It is intended to be fast, extensible, and secure. It is especially extensible in regard to its authentication subsystem. Supported authentication mechanisms include auth-pam (Pluggable Authentication Modules) and auth-passwd to mediate access between users and their Unix-style mailboxes, auth-mysql which uses vmail-sql to mediate access to virtual-domain email, auth-ldap which allows authentication of users against an LDAP directory, auth-other which allows you to authenticate with an external program communicating via pipes, and auth-perl which allows you to authenticate users with custom Perl code. There is integrated support for POP-before-SMTP relaying. tpop3d supports traditional (BSD-format) mailspools and the maildir format of qmail.