Cacti takes information from RRDtool and uses it produce more advanced graphs. It also offers an intuitive interface and some management capabilities. Operating System: Windows, Linux.
While most of the tools on our list are designed for run-of-the-mill networks, this tool from the University of California, Berkeley Millennium Project monitors high-performance computing systems such as clusters and grids. It's been around since 2000, and it's currently used on thousands of clusters around the world. Operating System: Linux, others.
Calling itself "the enterprise-class monitoring solution for everyone," Zabbix can monitor up to 100,000 networked devices for 1 million metrics, performing thousands of checks per second. It's completely open source, but Zabbix does offer paid support and other services. Operating System: Windows (agent only), Linux, OS X.
36. Pandora FMS
This "Flexible Monitoring Solution" can be set up to track anything from network status to website defacement to stock market trends. It generates real-time graphs, sends custom alerts, creates SLA reports and much more. Operating System: Windows, Linux, OS X.
Short for "Network Diagnostic Tool," NDT is a client/server app that offers network performance testing. It can help identify problems such as duplex mismatch conditions on Ethernet/FastEthernet links, incorrectly set TCP buffers in the user’s computer, or problems with the local network infrastructure. Operating System: Linux.
This set of applications implements SNMP v1, SNMP v2c and SNMP v3 protocols for both IPv4 and IPv6. These are command line tools, so they're not quite as user friendly as some of the other network monitoring applications. Operating System: Windows, Linux.
This tool allows network engineers and administrators to simulate complex systems in order to design networks or to study for certification exams. There's a tutorial and extensive documentation on the site to help new users learn how to use the application. Operating System: Windows, Linux, OS X.
This open source storage platform allows end users to store and share files across Windows, Mac, Linux and Unix-like systems. Key features include thin provisioning, backup and restore, snapshots, zettabyte file system and a Web interface. Operating System: FreeBSD.
41. Gluster FS
This distributed file system can scale up to 72 brontobytes while handling thousands of clients. A commercial version of the same software is available through Red Hat. Operating System: Linux.
Openfiler offers unified storage incorporating both NAS and SAN features. Its customers include Motorola, Pratt & Whitney, BillMeLater and the London Metropolitan Police. Commercial support and plug-ins are available. Operating System: Linux.
The "world's foremost network protocol analyzer," Wireshark allows administrators to capture network traffic and browse it interactively. Features include deep inspection of hundreds of protocols, live capture and offline analysis, powerful display filters, VoIP analysis and much more. Operating System: Windows, Linux, OS X.
Although it lacks a user-friendly GUI, this command-line tool offers powerful packet analysis capabilities. Not that the same site also features the libpcap library for network traffic capture. Operating System: Linux.
This is the version you'll need if you want to run tcpdump on Windows. It also includes the WinPcap library and drivers for traffic capture. Operating System: Windows.