Citadel is an advanced messaging and collaboration system for groupware and BBS applications. Users can connect to Citadel using any telnet, WWW, or client software. Among the features supported are public and private message bases (rooms), electronic mail, real-time chat, paging, shared calendaring, address books, mailing lists, and more. Unlike other collaboration servers, Citadel provides its own data stores and is therefore extremely easy to install; you don't have to "bring your own" email and database because they're built in. The server is multithreaded and scalable. In addition, SMTP, IMAP, and POP3 servers are built-in for easy connection to Internet mail. Citadel is both robust and mature; it has been in production since 1987.
getmail is intended as a simple, secure, and reliable replacement for fetchmail. It retrieves email (either all messages, or only unread messages) from one or more POP3, SPDS, or IMAP4 servers (with or without SSL) for one or more email accounts, and reliably delivers into qmail-style Maildirs, mboxrd files, or through external MDAs (command deliveries) specified on a per-account basis. getmail also has excellent support for domain (multidrop) mailboxes, including delivering messages to different users or destinations based on the envelope recipient address.
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.
Arb-Scan is a remote banner scanner written in bash and Perl. It supports 12 different services banner checks (daytime, ftpd, sshd, smtpd, domain, finger, httpd, pop2, pop3, nntp, imapd and snpp). It features IP file reading, logging, random IP scanning, ftp anonymous login checking and VRFY/EXPN smtp checking.
Replex is an administrative tool for managing email on any Unix-like OS. It can handle multiple domains, users, mailing lists, etc. without requiring creation of Unix user accounts for mailboxes or authentication. Replex is written in PHP4 and stores all information in a MySQL database. Replex relies on Postfix for SMTP and Cyrus for IMAP and POP3 accounts.
The Courier IMAP/POP3 maildir creation patch adds the ability to automatically create a user's home directory when he/she is successfully authenticated for the first time. It works by calling an admin-created script that takes care of creating the directory. It is quite useful in combination with authentication-modules based on network databases like MySQL or LDAP.
popbsmtpd watches syslog for successful POP and IMAP logins, and writes IP address entries to a database to permit SMTP mail relaying for a configurable duration. No changes to any other software are required, and it can process logins where the IP address and the authentication success are recorded on separate log entries (i.e., when using stunnel). It has a user-configurable scheme for recognizing and extracting values from log entries, making it possible to use with many POP and IMAP daemons without requiring any programming changes. These configurations can be tested using sample log data.