Network security toolbox

Ping and tracert are great, but sometimes you need a more powerful utility when troubleshooting your network -- especially where security is concerned. Check out these 12 free network security tools -- from scanners to network mappers -- that we've compiled into our network security toolbox.

Security in the work place begins and ends with the strength of your network security. One successful attack can lead to information leaks, malware infections and can practically bring your company's daily activity to a screeching hault. Check out these 12 free tools from to prevent these attacks from crippling your network.

[email protected] Network Monitor Engage Packet Builder Netcat
Snort Sysmon Nmap
Ethereal LanSpy 2.0 TCPView 2.34
SoftPerfect Network Scanner SuperScan v4.0 NetStumbler

[email protected] Network Monitor

[email protected] Network Monitor is an advanced network monitor, that automatically detects and analyzes your network nodes, including operating system. The program can monitor the nodes and alert you of any changes (new nodes, offline nodes etc.). The main window lists all available nodes and detailed statistics and scan results are available for each individual machine, including a real-time traceroute report, ping results, active services (open ports) and more. In addition to the auto-detected nodes, you can also customize the scan ranges and add additional networks.

Additional features include (but are not limited to):

  • HTML reports
  • Statistical graphs
  • Network tree view
  • Single node scanning

Download [email protected] Network Monitor
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Snort - Intrusion Detection

Snort® is an open source network intrusion prevention and detection system utilizing a rules-driven language which combines the benefits of signature, protocol and anomaly based inspection methods. With millions of downloads to date, Snort is the most widely deployed intrusion detection and prevention technology worldwide and has become the de facto standard for the industry.
Download Snort here
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Ethereal is used by network professionals around the world for troubleshooting, analysis, software and protocol development, and education. It has all of the standard features you would expect in a protocol analyzer, and several features not seen in any other product. Its open source license allows talented experts in the networking community to add enhancements. It runs on all popular computing platforms, including Unix, Linux, and Windows.
Download Ethereal
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SoftPerfect Network Scanner

SoftPerfect Network Scanner is a free multi-threaded IP, NetBIOS and SNMP scanner with a modern interface and several advanced features. It is intended for both system administrators and users who are interested in computer security. The program pings computers, scans for listening TCP ports and shows what types of resources are shared on a network (including system and hidden). p>In addition, it allows you to mount shared resources as network drives, browse them using Windows Explorer, filter the results list and more. SoftPerfect Network Scanner can also check for a user-defined port and report if it is found open, resolve host names and auto-detect your local IP range.

Main features include:

  • Fast multithreaded scanning
  • Pings computers
  • Detects hardware (MAC) addresses
  • Detects hidden shared resources (normally not visible on a network) and write accessible shares
  • Scans for listening TCP ports and SNMP services
  • Mounting and exploring of found resources
  • Doesn't require administrative privileges

Download SoftPerfect Network Scanner
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Engage Packet Builder

Packet injection starting from link layer (MAC address spoofing), supporting TCP. UDP and ICMP protocols
Download Engage Packet Builder
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Network monitoring tool designed to provide high performance and accurate network monitoring. Currently supported protocols include SMTP, IMAP, HTTP, TCP, UDP, NNTP, and PING tests.
Download Sysmon
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LanSpy 2.0

You can use LanSpy to find out who works on a remote computer, what kind of OS is installed or learn almost anything else about a remote computer in just a few seconds.

LanSpy is made for gathering the following information about a remote computer:

  • Ping
  • Domain name
  • NetBios names
  • MAC address
  • Server information
  • Domain (working group) information
  • Domain controllers
  • Remote control
  • Time
  • Disks
  • Transports
  • Users
  • Logged users
  • Global groups
  • Local groups
  • Security options
  • Shared resources
  • Sessions
  • Open files
  • Services
  • Processes
  • Registry
  • Event log
  • TCP ports
  • UDP ports

  • Download LanSpy 2.0
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    SuperScan v4.0

    SuperScan 4 is an update of the Windows port scanning tool, SuperScan.

    New features in this version include:

    • Superior scanning speed
    • Support for unlimited IP ranges
    • Improved host detection using multiple ICMP methods
    • TCP SYN scanning
    • UDP scanning (two methods)
    • IP address import supporting ranges and CIDR formats
    • Simple HTML report generation
    • Source port scanning
    • Fast hostname resolving
    • Extensive banner grabbing
    • Massive built-in port list description database
    • IP and port scan order randomization
    • A selection of useful tools (ping, traceroute, Whois etc)
    • Extensive Windows host enumeration capability

    Download SuperScan v4.0
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    Netcat is a featured networking utility which reads and writes data across network connections, using the TCP/IP protocol.

    It is designed to be a reliable "back-end" tool that can be used directly or easily driven by other programs and scripts. At the same time, it is a feature-rich network debugging and exploration tool, since it can create almost any kind of connection you would need and has several interesting built-in capabilities.

    It provides access to the following main features:

    • Outbound and inbound connections, TCP or UDP, to or from any ports.
    • Featured tunneling mode which allows also special tunneling such as UDP to TCP, with the possibility of specifying all network parameters (source port/interface, listening port/interface, and the remote host allowed to connect to the tunnel).
    • Built-in port-scanning capabilities, with randomizer.
    • Advanced usage options, such as buffered send-mode (one line every N seconds), and hexdump (to stderr or to a specified file) of trasmitted and received data.
    • Optional RFC854 telnet codes parser and responder.
      Download Netcat
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    Nmap ("Network Mapper") is a free open source utility for network exploration or security auditing. It was designed to rapidly scan large networks, although it works against single hosts. Nmap uses raw IP packets to determine what hosts are available on the network, what services (application name and version) those hosts are offering, what operating systems (and OS versions) they are running, what type of packet filter and /firewalls are in use, and dozens of other characteristics. Nmap runs on most types of computers and both console and graphical versions are available. Nmap is free software, available with full source code under the terms of the GNU GPL.
    Download Nmap
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    TCPView 2.34

    TCPView is a Windows program that will show you detailed listings of all TCP and UDP endpoints on your system, including the local and remote addresses and state of TCP connections. On Windows NT, 2000 and XP TCPView also reports the name of the process that owns the endpoint. TCPView provides a more informative and conveniently presented subset of the Netstat program that ships with Windows. The TCPView download includes Tcpvcon, a command-line version with the same functionality.
    Download TCPView 2.34
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    NetStumbler is a tool for Windows that allows you to detect Wireless Local Area Networks (WLANs) using 802.11b, 802.11a and 802.11g.

    It has many uses:

    • Verify that your network is set up the way you intended.
    • Find locations with poor coverage in your WLAN.
    • Detect other networks that may be causing interference on your network.
    • Detect unauthorized "rogue" access points in your workplace.
    • Help aim directional antennas for long-haul WLAN links.
    • Use it recreationally for war driving.

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    Related information from
    • Troubleshooting your Windows-based VPN
    • Securing the internal Windows network
    • Troubleshooting a Windows-based network
    • Step-by-step guide: Network Access Quarantine Control

    This guide originally appeared on

    This was last published in June 2006

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