Hermes SEG
Hermes SEG is a free, open-source secure email gateway and server. It delivers spam, virus, and malware protection using SpamAssassin, ClamAV, and Amavisd-new, along with full encryption in transit and at rest via SMTP TLS, S/MIME, PGP, encrypted PDF (CipherMail), and Dovecot mail-crypt. It includes email archiving and integrated mailbox hosting with quotas, aliases, shared folders, Sieve rules, vacation replies, and mobile auto-configuration. Collaboration features come through Nextcloud (webmail, file sync, calendars, contacts). Identity and access are managed with OpenLDAP and Authelia, supporting SSO and MFA (TOTP, WebAuthn, Duo). It also enforces modern authentication standards: SPF, DKIM, DMARC, and ARC.
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SpamAssassin
Welcome to the home page for the open-source Apache SpamAssassin Project. Apache SpamAssassin is the #1 Open Source anti-spam platform giving system administrators a filter to classify email and block spam (unsolicited bulk email). It uses a robust scoring framework and plug-ins to integrate a wide range of advanced heuristic and statistical analysis tests on email headers and body text including text analysis, Bayesian filtering, DNS blocklists, and collaborative filtering databases. Looking for tips to improve your existing installation? Click here for a variety of topics in our Wiki that might help. SpamAssassin uses a wide variety of local and network tests to identify spam signatures. This makes it harder for spammers to identify one aspect which they can craft their messages to work around.
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eM Client
Boost your email and skyrocket your productivity with the best email client for Windows and macOS.
eM Client is a fully-featured email client with a clean and easy-to-use interface. It also offers features for calendars, tasks, contacts, notes, and chat.
eM Client's compatibility is unmatched. You can connect to any email service – it will work. This email client works seamlessly with Google Workspace, Office 365, Outlook, Exchange and virtually all conceivable email technologies.
Integrates with Online meeting tools such as Zoom, MS Teams, Google Meet and more.
eM Client enhances email communication for professionals and home users alike. It is the only email app on the market with the full support of server-side rules and search, instant message translation, "Snooze email" and “Watch for reply” features + easy to use email encryption (PGP and S/MIME). It also works perfectly with Gmail, including support for tags and signature synchronization.
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Clyton
Clyton is an email client with advanced security and spam filtering features. The spam filter is highly configurable and supports DNS blacklist checking (DNSBL). Expect 85% of spam to be eliminated with the default configuration. Email that is suspicious but not obviously spam is quarantined for 24 hours and then retested, providing the blacklist enough time to react to new spam sources. The built-in address book supports personalized mass-mailings. Received email cannot run scripts, download multimedia, or use embedded objects without your approval. Other features include encrypted storage, whitelisting, powerful HTML editor, attachment viewer, message drag and drop, custom message templates, SSL encryption, USB flash drive installation, and much more.
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