20 free software favorites

Freeware applications and open source software that provide IT managers with great tools at no cost.

Network managers have long turned to freeware applications and open source software to address pain points without breaking the bank. The applications offer quick fixes to management and security issues with no budget approval and often become core to IT toolboxes. Here we highlight 20 freeware and open source tools, some that are well established and others that are newcomers to the free software game. 

What it is: Argus is a software application that monitors systems and network devices such as routers for availability and alerts IT managers when there are potential performance problems.

Key features: Argus features an intuitive Web interface, monitors network connectivity as well as system availability, and generates graphs on what is happening across the network. The software also can escalate alerts and notify network managers when problems aren't addressed within a predetermined time.

Where to get it: Argus is available for free download here under the open source Artistic License.

What it is: Cacti is a data collection, storage and graphing tool that lets network managers poll data from multiple sources and create visual representations of information across complex networks.

Key features: Cacti is available free for use under the GNU General Public License (GPL) and can tap SNMP for those network managers using MRTG or other traffic graphing tools.

Where to get it: Click here to download Cacti at no cost.

What it is: Clam AntiVirus is an open source antivirus toolkit for Unix that was designed to scan e-mails on mail gateways.

Key features: ClamAV includes utilities such as a multi-threaded daemon, a command-line scanner and an advanced tool for automatic database updates. The core of the open source package is an antivirus engine available in the form of a shared library, and the application includes built-in support for almost all mail file formats.

Where to get it: ClamAV is available for download under the GPL here

What it is: The freeware application FastSCP, introduced in 2006 by virtual systems management start-up Veeam, promises to provide file management capabilities for VMware ESX Server users.

Key features: FastSCP (Fast and Secure Copy) enables IT managers to transfer files between ESX Server and Windows machines, without reconfiguring the ESX Server.

Where to get it: FastSCP is freeware available for download here from virtualization systems management software maker Veeam.

What it is: jManage  is an open source application management platform. It provides a centralized console for managing application clusters and distributed application environments.

Key features: The jManage platform includes dashboards, alerts, graphs, security features and SNMP support. The software is designed to manage applications in development, quality assurance, staging and production environments.

Where to get it: jManage is available under the Apache Software License and can be downloaded for free here.

What it is: Kismet is an 802.11 Layer 2 wireless network detector, sniffer and intrusion detection system. It works with any wireless card that supports raw monitoring mode.

Key features: Kismet is able to identify networks by passively collecting packets and detecting named, hidden and non-beaconing networks via data traffic. The software can provide graphical mapping of networks, perform hidden network SSID de-cloaking and output data via XML.

Where to get it: Kismet is available for download here via GNU GPL under the GNU Privacy Guard Key.

What it is: Kiwi Syslog Daemon is a freeware Syslog Daemon for Windows that receives messages from network devices and displays them in real time.

Key features: The freeware "receives, filters, logs, displays and forwards Syslog messages and SNMP traps from such hosts as routers, switches, Unix systems and other Syslog-enabled devices," according to its keeper, Kiwi Enterprises.

Where to get it: Kiwi Syslog Daemon is available as freeware and downloadable here.

What it is: MRTG (Multi Router Traffic Grapher) is a tool that graphs router and other network device traffic by monitoring SNMP and creating visual images of the traffic passing through each interface.

Key features: MRTG is free software licensed under the GNU GPL that works on Unix, Linux, Windows and Netware. The software can track traffic on network devices and show network managers the bandwidth hogs, chatty protocols and end users potentially tapping applications they shouldn't.

Where to get it: MRTG is available free for download here.

What it is: Nagios is an open source host and service monitoring application designed to run under the Linux operating system, but also works on other platforms as well.

Key features: Nagios, built out of the project formerly known as NetSaint, monitors network services such as SMTP, POP3, HTTP, NNTP and more. The software also monitors host resources such as processor load, disk and memory usage, running processes and log files. It can incorporate environmental factors such as temperature. The open source application can also be customized by network managers via plugins.

Where to get it: Nagios can be downloaded under the GNU GPL 2.0 here.

What it is: The NetFlow Configurator utility, available from management software maker SolarWinds, lets IT managers unfamiliar with the command-line options for configuring NetFlow set up NetFlow on supported Cisco devices.

Key features: The utility also helps network managers set up collectors for Cisco NetFlow data by specifying the ports on which the collectors are listening and enabling monitoring of inbound and outbound traffic data per interface, SolarWinds says.

Where to get it: SolarWinds requires network managers to register to download the NetFlow Configurator utility here.

What it is: Nmap is a free, open-source security scanning utility that scans networks for network exploration, inventory or security auditing purposes.

Key features: Designed to rapidly scan large networks, Nmap runs on all major operating systems and uses raw IP packets to determine which hosts are available on the network, which services those hosts are offering, what operating system they are running and what types of packet filters and firewalls are in use.

Where to get it: Nmap (and its graphical front-end Zenmap) is distributed under the GNU GPL and is available free for download here.

What it is: NTOP is a network traffic probe that can sort network traffic according to protocols, display traffic statistics, show IP traffic distribution among protocols, and identify e-mail addresses of computer users, among other things.

Key features: NTOP lets network managers sort network traffic based on various criteria, analyze IP traffic based on source and destination, act as a NetFlow/sFlow collector for flows generated by routers or switches, and produce RMON-like network traffic statistics.

Where to get it: NTOP is distributed under the GNU GPL and is available free for download for Unix here.

What it is: OpenNMS is an enterprise-grade network management platform developed under the open source model and supported both by community and commercial efforts.

Key features: OpenNMS enables network managers to perform service polling to determine the availability of managed nodes, as well as collect data to store, report and establish thresholds. It also includes event notification and management capabilities.

Where to get it: Available under Version 2 of the GNU GPL, OpenNMS can be downloaded here.

What it is: PingPlotter Freeware is a traceroute application that allows network managers to trace the route between them and a target and collect performance metrics about that route.

Key features: The software application can deliver packet loss and latency numbers and display them in a graphical format. The visualization can help network managers more quickly determine which hop on a route is causing performance problems, according to PingPlotter.com.

Where to get it: PingPlotter Freeware is available for download here.

What it is: PuTTY is a client for Secure Shell (SSH) and Telnet connections that enables network managers to run a remote session on a computer over a network. PuTTY implements the client end of the session.

Key features: PuTTY uses cryptography to secure the connection against eavesdropping, hijacking and other attacks, according to its developer. The software application supports SSH1, SSH2 and Open SSH as well as Telnet and Rlogin.

Where to get it: The PuTTY executables and source code are distributed under the MIT license, which is similar in effect to the BSD license. The MIT license is compatible with the GNU GPL as well. Click here to download.

What it is: Scrutinizer is a NetFlow and sFlow analyzer that accepts unlimited flows from routers, switches and network interfaces to help network managers better understand the top talkers in their environments.

Key features: Scrutinizer can identify top hosts, top application per hosts, top hosts per applications and provide network mapping. The software integrates with third-party applications and is able to notify service providers if intruders are coming from their networks.

Where to get it: Network managers can download a free version of Scrutinizer here.

What it is: Snort is an open source network intrusion prevention and detection system that uses a rule-driven language to combine several methods of protecting networks, such as signature, protocol and anomaly-based inspection practices.

Key features: Snort has three primary uses: It can be used as a straight packet sniffer like tcpdump, a packet logger (useful for network traffic debugging, for example), or as a full-blown network intrusion prevention system.

Where to get it: Download Snort under the GNU GPL here.

What it is: UltraVNC is a free software application that enables network managers to remotely control the screen of another computer from their own workstation via the Internet or a network connection.

Key features: IT staff and help desk workers can use UltraVNC to more quickly address end-user performance problems and fix computers located at remote sites without sending a technician to the client desktop. The application also enables file transfers between computers.

Where to get it: UltraVNC is available free for download here.

What it is: Network protocol analyzer Wireshark, which was formerly named Ethereal, works on Windows, Linux, OS X and Unix platforms to allow network managers to examine protocol data from a live network or from a capture file on disk.

Key features: Wireshark is freely available open source software that provides deep inspection of hundreds of protocols, examines VoIP application traffic and performs live data capture with offline analysis.

Where to get it: Click here to download Wireshark at no cost under the GNU GPL.

What it is: ZipTie is a framework for network inventory and configuration management that allows network managers to discover devices in their network, create an inventory and manage the configurations of those devices.

Key features: ZipTie performs discovery, backup and restoration of network device configurations as well as provides a comparison of device configurations over time. The software offers a vendor-agnostic approach to managing configurations across varied vendor gear.

Where to get it: ZipTie is available via the Mozilla Public License here.

Is your favorite freeware or open source application not on the list? We want to hear from you. Tell us about the tools you use and why.