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.
poplimitd is a daemon process that monitors a server maillog file for POP3 or IMAP connections. Using configurable settings it monitors the rate of logins based on the user account and IP address. If it finds excessive usage, it will send a preconfigured email with the users information to that user asking them to stop. On servers that suffer from high POP3/IMAP load, this can dramatically modify user behaviour and limit POP and IMAP connections and load.
quickmail.php is a script that reads email from a mail server and outputs it in RSS format that can be displayed in a browser (as XML, using included XSL/CSS) or an RSS aggregator or as WML for use on WAP devices (mobile phones/PDAs). The output has been tested and found to be valid XSL/CSS, valid XML/RSS, and valid WML.
The QmailToaster is an RPM-based Qmail distribution for CentOS, Fedora, SuSE, and Mandriva. This system is designed for ease of deployment and includes strong anti-spam systems. This includes support for SRS, SPF, DomainKeys, and virtual hosting on the SMTP side. On the user side, this has a Web-based administration interface and supports POP3, POP3 over SSL, IMAP, and IMAP over SSL.