Atmail is a fully-featured email server and Webmail client, allowing users to send and receive email via a Web browser or mobile device. It has full support for IMAP mailboxes, and an optional email-server mode that uses EXIM as the MTA. Features include a scheduler, MySQL backend support, spell-check, address book, calendar user preferences, multiple accounts, SpamAssassin support, migration scripts from other mail servers, a customizable interface, an attractive AJAX interface, an optional group sharing Calendar/Addressbook, and an Outlook plugin to sync Contacts/Tasks/Calendar data between a Desktop, Mobile, and Webmail client or other email users.
Thunderbird is a total redesign of the Mozilla mail component to produce a cross-platform, stand-alone mail application using the XUL user interface language. It has many new features, among them the ability to customize your toolbars the way you want them. a new look and feel with a large number of downloadable themes which alter the appearance of the client, and the ability to add UI extensions.
Z1 CertServer (formerly Z1 Backbone Of Trust CertServer) is a server-based software solution for the storage and administration of X.509 certificates and OpenPGP keys. It targets customers who use a public key infrastructure (based on X.509 or OpenPGP) and who want to take advantage of the central access to certificates. It also automatically validates certificates by querying certificate revocation lists (CRLs) from the issuing trust centers, or by using OCSP (Online Certificate Status Protocol). Java and C/C++ SDKs are provided. It is available as pre-installed hardware or a virtual appliance, with evaluation packages for Debian and Solaris.
piler is an email archiving application with all the features required for an average company. The most prominent features are full text searching, deduplication, compression, encryption, digital fingerprinting, policy rules, access control, a built-in SMTP server, and Active Directory/openldap support.
Inbucket is an email testing service. It accepts messages for any email address and makes them available to view via a Web interface. It allows Web developers, software engineers, and system administrators to quickly see the emailed output of their applications. No per-account setup is required. Mailboxes are created on the fly as mail is received for them, and no password is required to browse the content of the mailboxes.