Used by more than 1,300 corporations with more than 2 million mailboxes, Scalix offers an alternative to a Microsoft Exchange server. It offers e-mail and calendaring, with excellent Outlook support. It's available in a free community version or paid small business, enterprise or hosting versions. Operating System: Linux.
The Zimbra Collaboration Suite calls itself "the worlds most sophisticated web application suite" and describes itself as "a next-generation Microsoft Exchange server." The open source server and the desktop client are available for free; the appliance and network editions require a fee. Operating System: Linux, Unix, OS X.
This ERP solution for multi-site, multi-national corporations offers dashboards, reporting, customer history, and many other features. It can be deployed on-premise or in the cloud via Amazon's EC2. The community version is completely open source, while the professional and enterprise versions add more functionality and paid support with a commercial license. Operating System: Windows, Linux, OS X.
39) Open ERP
This ERP suite offers CRM, purchasing, manufacturing, warehouse management, project management, accounting, human resources and marketing capabilities. Open ERP charges no fees for licenses, but does charge for support and on-site deployment services or SaaS subscriptions. Operating System: Windows, Linux.
Opentaps proclaims itself "the most advanced open source ERP + CRM solution." The full software is available with an open source license, or you can purchase a subscription to the Professional Edition, which includes updates and technical support. Operating System: Windows, Linux.
The most popular open source ERP solution in Germany, project-open combines ERP features with project management features. The base software is available on an open-source basis, while additional modules, support and other services are available for a fee. It's also available on an SaaS basis. Operating System: OS Independent.
xTuple's software helps businesses of all sizes keep track of sales, accounting, customers suppliers, inventory, manufacturing and distribution. The PostBooks edition of the software is available with an open source or a commercial license, and the Standard and Manufacturing editions are available with a commercial license only. Operating System: Windows, Linux, OS X, mobile OSes.
With Endian's open source software, you can turn any old PC into a unified threat management appliance to protect your network from all kinds of threats. Or you can purchase hardware or supported virtual appliances based on the same software. Operating System: Linux.
44) NetCop UTM
NetCop UTM combines the best open source security products into a single UTM solution. It comes in three versions: Free (for up to 5 users), SME (for less than 20 users) and Enterprise (for more than 20 users). Operating System: Linux.
Used by more than 30,000 organizations, Untangle includes a Web filter, virus blocker, spam blocker, ad blocker, firewall, QoS, intrusion prevention, protocol control, OpenVPN, and all the other capabilities you would expect in a UTM appliance. As with Endian, you can use it to build your own appliance, or you can purchase a hardware appliance or a software package that adds more features not found in the open source version. Operating System: Linux.
Open Applicant helps HR professionals and hiring managers sort through potential candidates to find the best applicant for a job. The application is free to download, but enterprise level support, customization, an SaaS version, and other services can be purchased from the company. Operating System: OS Independent.
47) Orange HRM
With more than 1 million users, Orange calls itself "the worlds most popular open source human resource management software." The software itself is free, but Orange also offers commercial support, training, add-ons, customization and an SaaS version. Operating System: Windows, Linux, OS X.
Staking its claim as the "leader on-premise and in the cloud," RedHat's JBoss encompasses a variety of middleware offerings. The community versions are free, while enterprise subscriptions add support and other services.
This brainstorming and mind mapping software makes it easy to see the connections between ideas. The professional version adds features for business users, like export tools and Gantt views, that aren't available in the free open source version. Operating System: Windows, Linux, OS X.