Seven Free Network Tools for the Busy Admin

by Aaron Leskiw [Published on 16 March 2010 / Last Updated on 16 March 2010]

Taking a look at seven free networking tools that will help the busy Admin.

Introduction

Budget cuts are commonplace these days. With less money available to invest in staff and new tools, I have compiled a list of seven free networking tools that will make your day-to-day job a little easier. Most are small and require no installation, perfect for carrying around on a USB stick!

1. Bring Ping and Traceroute to Life with Pingplotter

Download: http://www.pingplotter.com/freeware.html

Freeware: Windows

Pingplotter combines basic Ping and Traceroute commands into an easy to use graphical interface. Advantages of using Pingplotter are many. It will perform multiple traces to whatever destination you specify, then combine and graph the results. The graph including an average trend line, with min, max, and last results plotted on the line. Recently traced addresses are stored in the history on the left, saving you typing for addresses you check frequently. Export results as text, or as an image of the plot. Pingplotter has become the first tool I use when I suspect a system is in trouble.


Figure 1: PingPlotter Freeware

2. Who Is Using My Network? Find Out with Angry IP Scanner

Download: http://www.angryip.org/w/Download

Open-Source: Windows/Mac/Linux

Angry IP Scanner is another fast, lightweight tool. It requires no installation and is easy to use. Enter the IP range you want to scan and click Start. In a few moments you will have a list of all the devices on the network, including hostnames and open ports. Here is a list of possible uses:

  • Scan your network to see if anyone has plugged in unauthorized devices - like rogue WiFi access-points
  • Do you have building electrical maintenance planned? Instruct your users to shut down when they go home, then scan the network to see if any machines were accidentally left on
  • Use the port scan to do a basic check for possible vulnerabilities, or see if someone has installed web or mail servers that you don’t know about
  • Check to see how many free IP addresses you have on a subnet, then optimize your DHCP scope.

Tip:
Most personal firewalls will block ICMP (ping). If you have a windows network you can apply a group policy to allow ICMP from specific sources – like your administrator's machines.


Figure 2: AngryIP Scanner

3. Detect WiFi with inSSIDer from Metageek

Download: http://www.metageek.net/products/inssider/download

Open-Source: Windows

Metageek inSSIDer is a WiFi detector similar to the venerable Netstumbler – but it wins my vote for having been updated recently, and because it will run on Vista/Windows 7. It detects and displays all wireless networks in the area. Even better, it has a graphical display that shows at a glance which networks are detected, what channel they use, their hardware platform, and signal strength. Know instantly if your APs are fighting interference from other nearby networks, or if someone has installed rogue Access-Points and created possible security holes. Or, just use it to find out which open WiFi network is best for your iPhone.


Figure 3: Metageek inSSIDer WiFi detector

4. Dive Deep into the Network with Wireshark

Download: http://www.wireshark.org/download.html

Open-Source: Windows/Mac/Linux/Unix

For years Wireshark (formerly Ethereal), has been the go-to software for any serious network analysis. Few products have had this kind of staying power and it is easy to see why. Want to know what’s really happening on your network? Wireshark will capture packets, and then display them in a way that allows you to easily follow conversations and streams between computers. It has virtually endless sorting and filtering options to let you find the exact information you are looking for. And, it can analyze dumps from other software packages like MS Network Monitor.

5. Secure Telnet (SSH) with PuTTY

Download: http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html

Open-Source: Windows/Unix/Linux/Mac (unofficial port)

Repeat after me: I will not use Telnet, I will not use Telnet. While simple and fast, Telnet has its problems, with its major one being security since passwords are transmitted in clear text. The fix is easy, enable SSH on your network devices and use PuTTY as your terminal emulator. PuTTY is versatile and requires no installation. It supports Serial connections, and of course it can still do Telnet when needed. Support for copy/paste commands save you unnecessary keystrokes, and it also does Secure FTP.


Figure 4: Placing PuTTy as your terminal emulator

6. Don’t Lose Those Logs: Free Kiwi Syslog Server from SolarWinds

Download: http://www.solarwinds.com/Products/freetools/kiwi_syslog_server/

Free with Registration: Windows

Have you been frustrated because your logs disappeared after a helpful user power-cycled your router? Well, to prevent this you need a syslog server. SolarWinds’ free Kiwi Syslog Server comes to the rescue. Configure all your network devices to send logging messages to the syslog server, and never again wonder if some useful information was lost.

7. Measure Your Bandwidth with Iperf

Download: http://sourceforge.net/projects/iperf/

Open-Source: Code freely available, Linux/Windows binaries available with some searching

Iperf is a bandwidth testing tool that can help you find network problems. Are you suspecting that your 100Mb circuit is not performing very well? Throw the tiny Iperf executable on computers at each end of the connection, run a quick test and see how you fair. It requires no installation, and can measure TCP and UDP, jitter, and a number of other metrics.


Figure 5: Iperf bandwith testing tool

Note:
Some of these tools could be considered to be hacking tools by your company’s security policy. If in doubt, check with your network administrator before downloading or using any of them.

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