Free secure mail software for linux

Secure Messaging is a Web-based, alternative mail system for sending and receiving messages.

Use secure messaging to send and receive messages from a alternative web-based mail system. Using the secure messaging system no actual mail is transmitted through any 3rd party servers.

Only an optional message notice is sent to the recepient, the user needs to visit the site in order to read the message.

Normal SMTP mail can hit multiple servers and can possibly be read, stored, or changed anywhere within the process.

Setup secure messaging on an SSL enabled website to enhance the privacy even more.

Shohei is a multi-language, multi-function, multi-server, multi-user, multi-context, multi-media web-based mail client, news client, calendar and note server.
Shohei is a pop3 client which meets the requirements of Stockholm public network.
Main features:
- Sends mail using SMTP
- Receives mail using POP
- Handles users in any number of domains on any number of servers
- Web based administration with different admins for different domains
- MIME aware
- Usenet News client
- Online context-sensitive help
- Customizable using HTML templates with embedded macros
- Calendar
- Write simple notes
- English and Swedish message catalogs, new ones are easily added

Masswire Mail provides a SQL POP3 Webmail software.

Masswire Mail is a Webmail client written in Perl that can retrieve messages from multiple POP3 accounts and store them in a single SQL table.

Some features include a spell checker using the Text-Aspell module, a Bayesian filter using the Algorithm NaiveBayes module, and attachments using the Mail Sender module.

Remote Secure Command System project is a remote asynchronous and secure command system based on a file configuration.

A standalone server sends and receives commands through files, and a batch system launch ssh and scp commands.

Secure-SLinux provides a secure, stable, and slim OS for professional enterprise servers. Secure-SLinux is based on the Linux kernel and GNU glibc, and builds on HLFS/BLFS.
It is quick to install (5-10 minutes), hardened (GRsecurity, PAX, RBAC, SSP, frandom, etc.), and easy to administrate. There are precompiled binary releases for console only and XOrg-based systems.
Main features:
- open source
- secure - hardened OS
- robust
- easy to administrate - comes out of the box with everything you need for your everyday administrative tasks
- easy to update - simply move a single link and keep your old versions
- suitable for all professional enterprise servers
- cost effective
... and it is installed in just 5 minutes!
Enhancements:
- SSLX-Desktop is the desktop environment for Secure-SLinux. It is based on programs such as XFCE, Firefox, Thunderbird, Filezilla, GIMP, OpenOffice.org, Eclipse, Bluefish, and Xfe.

Orion Secure Message Gateway (OrionSMG) is a secure message gateway for transporting ebXML, SOAP, and custom message formats. It complies with the OASIS ebXML 2.0 specification, and can act in both intermediary and processing MHS roles to provide end-to-end reliable messaging.
Orion Secure Message Gateway software runs natively on Linux, OS X, and Windows with ODBC/PostgreSQL database support.
Enhancements:
- OrionSvnInfo.h now in correct directory.
- Old documentation temporarily added.
- Minimal README.txt file added.

Dwarf Mail Server is a full-featured mail server developed on the Java platform, implementing SMTP, POP3 and IMAP4rev1 protocols.
Dwarf Mail Server provides support for rich application message processing via pluggable mail filters and agents, as well as full handling of virtual domains for the SMTP/POP3/IMAP4 protocols, and is free of charge for the binary redistribution.
Since the server is based on the Dwarf framework, it also shares its common design principles and features - simplicity, high modularity and extensibility, authentication and authorization, XML-based configuration, logging and remote management.
Main features:
- ESMTP, POP3 and IMAP4rev1 implementation
- application logic layer provided by mail filters and agents
- virtual mail hosts in SMTP/POP3/IMAP4 server
- application-independent authentication and authorization
- sample JSP-based webmail interface
Dwarf Mail Server is targeted for both end users who are just looking for simple, secure and robust mail server as well as developers who need an extensible and powerful framework for application message processing.
For users with minimal requirements it can offer portability, simple configuration as well as strong security.
- Portability: several OS platforms are supported via the Java technology, including MS Windows, UNIX/Linux/BSD, MacOS X and others.
- Configuration: just 3 lines have to be changed to fire up a sample mail server and a few of them to run a full featured SMTP/POP3/IMAP4 server.
- Security: it uses Java Platform Security Architecture in combination with Java Authentication and Authorization Service (JAAS), as well as SSL/TLS for the secure communication.
Advanced or enterprise users can additionally appreciate performance scalability, multiple domain handling, enhanced security features and modular design easing to incorporate it to the existing infrastructure.
- Scalability: gaining from multithreaded design and dynamically adjustable allocation of resources.
- Multiple domains: server is able to handle multiple virtual domains in a single instance for all SMTP, POP and IMAP protocols.
- Enhanced security: includes subject-based permissions and access control lists for IMAP, SMTP relaying control rules, host-based filtering, SSL/TLS communication, basic anti-spam filtering, etc.
- Robustness: client/server network communication is by design separated from the resource-expensive application logic layer. The server implementation is based on the unparsed byte streams whenever possible, including its own and highly efficient MIME parser.
Dwarf Mail Server also appears to be a suitable platform for application development and customization. Its modular structure and lightweight API allows enhancing existing functionality or completely exchanging the certain part as a whole:
- Message processing: mail filters and agents provide an unique infrastructure for rich message processing.
- Mail queue: physical mail queue representation is abstracted by the API specification and may replaced by a custom implementation.
- Storage subsystem: physical data representation (i.e. messages, folders, configuration options, ACLs) is abstracted by API and may be replaced by a custom implementation based on filesystem, SQL database, etc.
- MIME parser: the parsing engine may be reimplemented for the top efficiency according to the currently used mail storage.
Dwarf Mail Sever has been tested with the most popular mail clients like MS Outlook, Mozilla, Thunderbird, Opera, Apple Mail, Becky!, Pegasus, Eudora, Pine, The Bat! and others.
Other features:
- multi-threaded server
- dynamically adjusted number of active threads
- server API for mail, user data and ACL storages
- robust SMTP server architecture with flexible queue design
- simultaneous deliveries to remote SMTP hosts
- transparent Delivery System Notification (DSN) mechanism
- support for shared mail folders
- fast and universal stream-oriented MIME parser
- runtime server configuration
- built-in SSL/TLS support
- full documentation with user guides and tutorials
- samples with source code

Enhancements: Compatible with TB 1.5.0.*

Requirements: Thunderbird 1.0 - 1.5.0.* ALL