Microsoft Exchange – On Premis or Hosted 365
Microsoft Exchange provides full and Seemless connectivity Between Desktop – Webmail and Mobile Devices. Group emails and Calenders.
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https://www.microsoft.com/en-au/microsoft-365/business/compare-all-microsoft-365-business-products?&activetab=tab:primaryr2
Lotus Notes and domino – cost effective Mail and group applications
IBM® Domino® Express is a security-rich, full-featured application environment for email, business and collaborative applications. This set of IBM messaging and collaboration offerings enables companies to acquire, deploy and use the capabilities of IBM Domino software. IBM Domino Express offerings are packaged and priced to provide cost-effective functionality for midsize companies with less than 1,000 authorized users.
IBM Domino Express is:
- Cost-effective—bringing enterprise features to midsize businesses at an affordable price. Per-user pricing is available.
- Security-rich—helping to protect your data with encryption and engineered to resist viruses.
- Easier to manage—automated installations, policies and monitoring minimizes your administration needs.
- Mobile—helping you stay connected using a variety of mobile devices while helping protect business assets.
- Compatible—supports thousands of independent software vendor applications.
Alt-N MDaemon – MDaemon from – For a Smaller site just wanting their own mail server.
Reliable Email Server, IM, Groupware, Web Mail and Mobile Device Management (MDM) in one download. Designed for SMBs with on premises or virtualized deployments.
Mail Server
MDaemon Messaging Server supports IMAP, SMTP, and POP3 protocols and delivers solid performance from its feature-rich and user-friendly design. The mail server software delivers low total cost of ownership (TCO) value designed to meet the needs of small- to medium-sized business customers. MDaemon is available in multiple languages and supports mailing lists, content filtering, multiple domains while offering flexible administration and an open standards design