50. Open Applicant
For companies besieged by job applicants, this software aims to make the process of finding the right employees easy and effective. It comes in open source, professional and hosted versions. Operating System: OS Independent.
51. Orange HRM
52. Snort
The "most widely deployed IDS/IPS technology worldwide," Snort combines signature, protocol, and anomaly-based network inspection into one package. The software is free, but a subscription gets you real-time access to rules updates. (Non-subscribers must wait 30 days.) Operating System: Linux, Unix, BSD, Mac OS X.
53. OSSEC
Downloaded more than 5,000 times every month, this popular host-based intrusion detection system (HIDS) offers features like a powerful correlation and analysis engine, integrating log analysis, file integrity checking, Windows registry monitoring, centralized policy enforcement, rootkit detection, real-time alerting and active response. Companies that need paid support can obtain it through OSSEC-owner Trend Micro. Operating System: Windows, Mac, Linux, Unix, BSD, Solaris.
54. JBoss
Used by companies like Priceline.com, GEICO and NYSE Euronext, RedHat's JBoss line of middleware includes an application platform, Web platform, messaging, SOA platform, business rules management system and much more. All of the tools are available in open source and enterprise versions. Operating System: Linux.
55. XMind
Ideal for brainstorming and planning sessions, XMind makes it easy to see the connections between ideas—it's sort of like a white board for your computer. In addition to the free version, it comes in a pro version for individuals and an enterprise version for businesses. Operating System: Windows, Linux, OS X.
56. Nagios
Calling itself the "industry standard in open source monitoring," Nagios counts Unisys, Wells Fargo, AVG, BT, Xerox, Citrix, iRobot, ADP, the Office of the President of the United States and many other organizations among its users. The paid Nagios XI version comes with a support and maintenance contract, but you can also purchase a support subscription for the Core open source version. Operating system: Linux, Unix.
Opsview aims to provide "a single pane of glass for managing and monitoring distributed IT infrastructures," including your cloud infrastructure and mobile devices connected to your network. The community version is free, but the paid enterprise version offers better scalability, reporting and other features. Operating System: Linux.
58. SNARE
Intersect Alliance, the company behind SNARE, offers free, open source downloads of its monitoring agents. For commercial support and a centralized view of event collection, analysis, reporting and archives, you can purchase the proprietary SNARE server. Operating System: Windows, Linux, Unix, Solaris.
59. Wireshark
"The world's foremost network protocol analyzer," Wireshark offers live capture and offline analysis of the traffic running across your network. The software is free, but Riverbed Technologies offers many products and services to enhance its capabilities. Operating System: Windows, Mac, Linux, Unix, BSD, Solaris.
60. Zabbix
This enterprise-class monitoring solution offers both agent and agentless monitoring, availability and SLA reporting, scalability to 100,000 devices, and more. Commercial support, training and other services are available. Operating System: Windows (agent only), Linux, OS X.
61.Red Hat
RedHat, which calls itself "the world's open source leader," offers one of the best known distributions of Linux. RedHat Enterprise Linux comes in desktop, server and several other versions. Note that RedHat is a paid product, but a community version is available through Fedora.
62. SUSE Novell counts the London Stock Exchange, Office Depot, Sony and Walgreens among the users of its SUSE Enterprise Linux. It comes in multiple desktop and server versions, including some optimized for virtualized or cloud computing environments. For the open source version, see openSUSE.
63. Ubuntu Used by more than 20 million people, Ubuntu comes in desktop, server, cloud and mobile editions. Professional support, services, training and consulting are available through the Canonical, which owns Ubuntu.
64. Onepoint Project
This Web-based application combines project management and project portfolio management into a single package. It comes in open source, group and enterprise versions, and the paid group and enterprise versions can be deployed on your own server or in the cloud. Operating System: Windows, Linux, OS X.
65. Vyatta
Vyatta offers both hardware appliances and networking software. Both are based on the open source software available through Vyatta.org. Operating System: Linux.
66. openSIS
This open source school information system (SIS) claims that it can save schools 75 percent versus commercial solutions. The free community edition is suitable for small or medium-sized schools with their own IT staff, while the SaaS school edition is for small or medium-sized schools who don't want the hassle of running their own servers. Large schools and districts should look at the district edition, which can run in the cloud or on premises. Operating System: OS Independent.
67. ClearOS
ClearOS combines a networking server, security gateway, file server, groupware server, Web server and more into a single download. All three versions—enterprise, home and core—are available on a free and open source basis, but paid software subscriptions, technical support, hardware and other services are available through ClearCare. Operating System: Linux.
68.Zentyal
Like ClearOS, Zentyal is a multi-function small business server with unified threat management, officer server, communications and other capabilities. The basic edition is free; small business and enterprise editions, training, and add-ons require a fee. Operating System: Linux.
69. Openfiler
Downloaded more than 1 million times, Openfiler incorporates both file-based Network Attached Storage (NAS) and block-based Storage Area Networking (SAN) in a single download. Subscriptions, plug-ins and an administrator's guide are available for a fee. Operating System: Linux
70. TimeTrex
The self-proclaimed "world's most popular open source payroll and time management software," TimeTrex handles scheduling, attendance, job costing and payroll functions. It comes in a free standard edition and paid pro and business editions; the pro and business versions can be purchased on an SaaS basis or deployed on site. Operating System: Windows, Linux, OS X.
71. WiKID
This software-based two-factor authentication system aims to be less expensive and more extensible than competing solutions. The paid enterprise server version adds support and some proprietary functionality not included in the free open source version. Operating System: OS Independent.