Open Source Linux Email Servers
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Email Servers for Linux
View 30 business solutionsBrowse free open source Email Servers and projects for Linux below. Use the toggles on the left to filter open source Email Servers by OS, license, language, programming language, and project status.
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Failed Payment Recovery for Subscription BusinessesFlexPay’s innovative platform uses multiple technologies to achieve the highest number of retained customers, resulting in reduced involuntary churn, longer life span after recovery, and higher revenue. Leading brands like LegalZoom, Hooked on Phonics, and ClinicSense trust FlexPay to recover failed payments, reduce churn, and increase customer lifetime value.
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PHPMailer
The classic email sending library for PHP
PHPMailer – A full-featured email creation and transfer class for PHP. Support for UTF-8 content and 8bit, base64, binary, and quoted-printable encodings. SMTP authentication with LOGIN, PLAIN, CRAM-MD5, and XOAUTH2 mechanisms over SMTPS and SMTP+STARTTLS transports. Validates email addresses automatically. Many PHP developers need to send email from their code. The only PHP function that supports this directly is mail(). However, it does not provide any assistance for making use of popular features such as encryption, authentication, HTML messages, and attachments. Formatting email correctly is surprisingly difficult. There are myriad overlapping (and conflicting) standards, requiring tight adherence to horribly complicated formatting and encoding rules – the vast majority of code that you'll find online that uses the mail() function directly is just plain wrong, if not unsafe! -
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MailHog
Web and API based SMTP testing
Inspired by MailCatcher, easier to install. Built with Go, MailHog runs without installation on multiple platforms. Run it from Docker Hub or using the provided Dockerfile. The SMTP server starts on port 1025, the HTTP server starts on port 8025, in-memory message storage. ESMTP server implementing RFC5321. Support for SMTP AUTH (RFC4954) and PIPELINING (RFC2920). Web interface to view messages (plain text, HTML or source). Supports RFC2047 encoded headers. Real-time updates using EventSource. Release messages to real SMTP servers. Chaos Monkey for failure testing. HTTP API to list, retrieve and delete messages. See APIv1 and APIv2 documentation for more information. HTTP basic authentication for MailHog UI and API. Multipart MIME support. Download individual MIME parts. In-memory message storage. MongoDB and file based storage for message persistence. Lightweight and portable. No installation required. -
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The Courier mail transfer agent (MTA) is an integrated mail/groupware server based on open commodity protocols such as ESMTP, IMAP, POP3, LDAP, SSL, and HTTP. Courier provides ESMTP, IMAP, POP3, Webmail, calendaring, and mailing list services.
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smtp4dev
The fake smtp email server for development and testing
smtp4dev - the fake SMTP email server for development and testing. A dummy SMTP server for Windows, Linux, Mac OS-X (and maybe elsewhere where .NET Core is available). Lets you test your application without spamming your real customers. -
Award-Winning Medical Office Software Designed for Your SpecialtyRXNT is an ambulatory healthcare technology pioneer that empowers medical practices and healthcare organizations to succeed and scale through innovative, data-backed, AI-powered software.
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Inbucket
Disposable webmail server (similar to Mailinator) with built in SMTP
Inbucket is an email testing application; it will accept messages from any email address and make them available to view via a web interface. When you need to test your webapp's outbound emails with Mailinator but are stuck behind a firewall, Inbucket provides the solution. It allows you to keep your new application development secret until it's time to release it. Inbucket is ideal for validating that emails go out as part of your integration test suite, sending links to coworkers to demonstrate an email without sharing your Gmail password, and load testing your application without overwhelming your corporate Exchange server. You can use production data in your test environment without the risk of test messages leaking to an end user, and preview emails in multiple desktop email clients. Use Inbucket for all these needs and more. -
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Mox
modern full-featured open source secure mail server
Mox is a modern email server written in Go that aims to be simple, secure, and standards-compliant. It includes SMTP, IMAP, DMARC, SPF, DKIM, and other protocols required to host email services. Designed for self-hosters and developers who want better control over their email stack, Mox focuses on code clarity, privacy, and correctness, offering a complete mail server solution that is easy to set up and maintain. -
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Mailu
Insular email distribution - mail server as Docker images
Mailu is a simple yet full-featured mail server as a set of Docker images. It is free software (both as in free beer and as in free speech), open to suggestions and external contributions. The project aims at providing people with an easily setup, easily maintained and full-featured mail server while not shipping proprietary software nor unrelated features often found in popular groupware. Security, enforced TLS, DANE, MTA-STS, Letsencrypt!, outgoing DKIM, anti-virus scanner, Snuffleupagus, block malicious attachments. Antispam, auto-learn, greylisting, DMARC and SPF, anti-spoofing. Freedom, all FOSS components, no tracker included. -
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PostfixAdmin is a Web Based Management tool created for Postfix. It is a PHP based application that handles Postfix Style Virtual Domains and Users that are stored in MySQL, PostgreSQL or SQLite
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Docker Mailserver
Production-ready fullstack but simple mail server
docker-mailserver provides a production-ready, all-in-one email server in a single container, focused on simplicity and maintainability. It bundles the core mail stack—Postfix for SMTP and Dovecot for IMAP/POP3—then layers in optional anti-spam and anti-virus services, DKIM/DMARC signing and verification, and rate-/abuse-protection tooling. The project emphasizes secure defaults while exposing configuration via environment variables and mounted files, allowing you to define users, aliases, domains, and sieve filters without rebuilding images. It integrates smoothly with Let’s Encrypt for TLS, supports LDAP and other auth backends, and ships with scripts to validate DNS records and common misconfigurations. Persistent volumes keep mailboxes and state, making upgrades straightforward and rollbacks less risky. Administrators appreciate the clear docs, test suite, and opinionated conventions that help avoid fragile bespoke setups. -
Outbound sales softwareAdversus is an outbound dialing solution that helps you streamline your call strategies, automate manual processes, and provide valuable insights to improve your outbound workflows and efficiency.
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PostfixAdmin
Web based virtual user administration interface for Postfix mail
PostfixAdmin is a web-based interface for managing mail domains, mailboxes, and aliases for Postfix mail servers. It allows administrators to add and configure virtual domains and email users easily, supporting MySQL, PostgreSQL, and SQLite as backend databases. It's widely used in self-hosted email setups for simplifying email management. -
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ISPConfig - ISP management and Hosting Control Panel. ISPConfig manages one or more webservers, mailservers, BIND DNS server, FTP servers, MySQL databases and virtual Servers with an easy to use webinterface for administrators, resellers and clients.
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Modoboa
Mail hosting made simple
Modoboa is a mail hosting and management platform including a modern and simplified Web User Interface. It provides useful components such as an administration panel and webmail. Modoboa integrates with well known software such as Postfix or Dovecot. A SQL database (MySQL, PostgreSQL or SQLite) is used as a central point of communication between all components. Modoboa is developed with modularity in mind, expanding it is really easy. Actually, all current features are extensions. It is written in Python 3 and uses the Django, jQuery and Bootstrap frameworks. Follow the evolution of your server traffic thanks to a few builtin graphics: messages distribution per type and average size. Easily use standard protocols like DKIM or DMARC to improve your sender reputation and so make sure your emails will be delivered. Consult your emails everywhere thanks to simple but functional builtin webmail. -
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mailcow
mailcow: dockerized
With the Nightly Branch, it is now possible to use an external Identity Provider as an additional authentication source. mailcow utilizes the OIDC (OpenID Connect) protocol to authenticate only mailbox users. You can also get a SAL which is a one-time payment with no liabilities or returning fees. mailcow makes use of various open-source software. Please assure you agree with their license before using mailcow. Any part of mailcow itself is released under GNU General Public License, Version 3. -
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Zentyal, Linux Small Business Server
Zentyal is a Linux Small Business Server
Zentyal Server is an easy to use and affordable Linux server, specially designed to meet the needs of small and medium businesses Thanks to Zentyal's Samba integration, Zentyal provides native compatibility with Microsoft Active Directory, allowing you to join Microsoft clients to a domain and manage them easily. Zentyal Server incorporates all the network services required in a small and medium business environment: * Directory & Domain Server with native compatibility with Microsoft Active Directory * Mail Server with ActiveSync and webmail * Gateway with firewall and proxy * Infrastructure Server with DNS/DHCP server, Certification Authority and Virtual Private Networks For more information and download, please access the project's home page. -
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Highly scalable/configurable Messaging Platform allowing users in a domain to be distributed on multiple hosts, has multiple queues. Provides virtual domains/users in MySQL. Modern MSP class qmail replacement with ESMTP, POP3/IMAP, QMTP, QMQP support
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YPOPs! is an application which emulates a POP3/SMTP mail server and provides free POP3 and SMTP access to Yahoo! Mail. It does not depend on Yahoo's POP3/SMTP mail server. You can use a mail client of your choice!
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NethServer
Linux for for small offices and medium enterprises
NethServer 7 is an operating system for Linux enthusiasts, designed for small offices and medium enterprises. Based on CentOS, the product's main feature is a modular design which makes it simple to turn the distribution into a mail server and filter, web server, groupware, firewall, web filter, IPS/IDS or VPN server. A comprehensive web-based user interface simplifies common administration tasks and enables single-click installation of several pre-configured modules. Stay tuned with NethServer 8! Follow the links on http://www.nethserver.org for more information -
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DKIMproxy is an SMTP-proxy that implements the DKIM and DomainKeys standards, to sign and verify email messages using digital signatures and DNS records. It can be used to add DKIM support to nearly any existing SMTP mail server.
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Small HTTP server
Universal server
It is not only a web server, it is also Mail server, DNS server, FTP server, Proxy server, VPN server and client... All in one! This program will help you to open all the possibilities Internet can offer for your company - public site, provide Internet access and personal mailboxes for each employee! HTTP server. Server Side Includes. Regular expression in SSI. CGI interface for scripts (Executable files; Perl,PHP, or another external interpreters) ISAPI interface. Virtual hosts and directories Mail POP3 server. SMTP server. FTP server HTTP proxy server DNS server DHCP server HTTP TLS VPN server -
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Haraka
A fast, highly extensible, and event driven SMTP server
Haraka is a highly scalable node.js email server with a modular plugin architecture. Haraka can serve thousands of concurrent connections and deliver thousands of messages per second. Haraka and plugins are written in asynchronous JS and are very fast. Haraka has very good spam protection (see plugins) and works well as a filtering MTA. It also works well as a MSA running on port 587 with auth and dkim_sign plugins enabled. Haraka makes no attempt to be a mail store (like Exchange or Postfix/Exim/Qmail), a LDA, nor an IMAP server (like Dovecot or Courier). Haraka is typically used with such systems. Haraka has a scalable outbound mail delivery engine built in. Mail marked as relaying (such as via an auth plugin) is automatically queued for outbound delivery. Haraka's plugin architecture provides an easily extensible MTA that complements traditional MTAs that excel at managing mail stores but do not have sufficient filtering. -
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Mail-in-a-Box
Take back control of your email with this mail server in a box
Mail-in-a-Box helps individuals take back control of their email by defining a one-click, easy-to-deploy SMTP+everything else server, a mail server in a box. Mail-in-a-Box lets you become your own mail service provider in a few easy steps. It’s sort of like making your own gmail, but one you control from top to bottom. Technically, Mail-in-a-Box turns a fresh cloud computer into a working mail server. But you don’t need to be a technology expert to set it up. Our goals are to make deploying a good mail server easy, promote decentralization, innovation, and privacy on the web, have automated, auditable, and idempotent configuration, not make a totally unhackable, NSA-proof server, and not make something customizable by power users. Mail-in-a-Box turns a fresh Ubuntu 18.04 LTS 64-bit machine into a working mail server by installing and configuring various components. It is a one-click email appliance. There are no user-configurable setup options. It "just works." -
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Postal
A fully featured open source mail delivery platform for incoming
Postal is a complete, open-source mail delivery platform for managing massively scalable outgoing email infrastructure—designed as a self-hosted alternative to SendGrid, Mailgun, or Postmark. It provides a web UI for managing email streams, logs, and delivery infrastructure. Postal is highly scalable and intended for developers and businesses needing reliable email dispatch. -
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Convert Webmail to POP3.Is also included a SMTP/POP3 tunneling system that allow send and receive email in a private network HTTP PROXY based. All connection are plugin based. Over 450 email server supported and tested, GMAIL POP3/SMTP over Proxy Network.
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MailCleaner
Anti Spam SMTP Gateway
MailCleaner Open Source Edition is now discontinued but will continue under the spamtagger project https://github.com/SpamTagger [antispam] MailCleaner is an anti-spam / anti-virus filter SMTP gateway with user and admin web interfaces, quarantine, multi-domains, multi-templates, multi-languages. Using Bayes, RBLs, Spamassassin, MailScanner, ClamAV. Based on Debian. Enterprise ready. MailCleaner is an anti spam gateway installed between your mail infrastructure and the Internet. It includes a complete GNU/Linux OS and a graphical web interface for user and administrative access. It comes in the form of virtual machine templates.. - fully compatible with any SMTP mail server (Exchange, Zimbra, O365,...) -
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Provide an Open Source Java Email Server that supports POP3/SMTP.
