CompTIA Certifications

CompTIA Network+ 2009 Domain 5: Network Tools

Studying for the Network+ certification exam is a fun process. The A+ certification is for entry level technicians, so you probably found it an easier task – something you could little to no studying for and still pass. The Network+ certification exam provides you a little more challenge, something with a little more technical depth and an experience I think you will enjoy.

In the first section of this tutorial, we’re going to discuss command line interface (CLI) tools – the software utilities you can use when working as a network administrator. For each tool, we will go into depth about what it is, how it’s used and show you an example of the output of the tool. First, let’s provide a summary of the networking tools we’re going to be teaching you. The tools we’re going to explore include:

IPConfig & Ifconfig – IPConfig and Ifconfig provide the same information: the IP address and network configuration information for the computer you are using.

Ping – Ping sends a signal from the machine you are using to a remote device and measures the time it takes for the packet of information to travel between the devices. This is useful to see if a machine across a network is responding to network requests.

Traceroute – Traceroute sends a signal from the computer you are using to some destination and displays the route between the devices.

Arp Ping -ARP, or Address Resolution Protocol, is used by hosts on a network to figure out the address of a particular network device. An ARP Ping will show whether a device is up in case normal pings are blocked on the network.

Arp – Address Resolution Protocol is used to translate an IP address into a media access control address – the unique address every networking device has encoded in it.

NSLookup – NSLookup is used to query domain name servers to find a domain name or an IP address.

Hostname – The hostname utility displays the hostname (the readable name) of the machine you are using. On Unix and Linux systems, you could use hostname to actually set the hostname of the system, but it’s typically set elsewhere.

Dig – Dig is similar to NSLookup for Unix, Linux, and Mac OS systems. Dig allows you to look up domain name information.

Mtr – Mtr (“my traceroute”) is a network diagnostic utility combining traceroute and ping into a single tool. It helps identify problems between routers or devices on a network.

Route – The networking drivers on your computer keep a routing table so the network interface card knows where to send information. Route allows you to view and manipulate the TCP/IP routing table.

Nbtstat – NBTStat is used to diagnosis NetBIOS over TCP/IP, a networking standard created by Microsoft for Windows networks.

Netstat – Netstat (network statistics) shows network connections, routing tables, and networking related statistics to help you troubleshooting a network performance problem.

Each of these utilities is going to be dissected and described in great detail, but based on the descriptions here and your existing networking knowledge, try your hand at these questions:

  1. Which networking utility will you most likely use to determine if a internal network router is responding?
  2. A user has called you with a problem accessing the network and you want to troubleshoot their problem from your command line interface. What two utilities could the user run to provide you the information you need to begin troubleshooting the problem?
  3. You work in a Windows networking environment. You want to find out information about a remote machine using the NetBIOS name. What utility will you use?
  4. You’d like to view the routing table on your computer. What command will you use?
  5. You know you have a problem between routers on your network, but you’re not quite sure where. What is the most likely tool you will you use to troubleshoot?

Answers to your quick quiz:

  1. The first utility you will use is ping. Ping sends a packet to a device requesting an echo back and then measures the time it takes to respond. It also responds if there is no reply indicating, possibly, the device is down.
  2. The first thing you need to know from the end user is the address of their machine – either the machine hostname or the IP address. You could use ipconfig (on Windows) or hostname to determine one of those pieces of information. I always ask for the IP address to rule out domain resolution issues.
  3. You will use nbtstat to find out information about a NetBIOS networked device. NBTStat provides statistics and detailed networking information given an IP address or hostname.
  4. You will use the command route to view the routing table on your computer.
  5. mtr is the best tool to use in a situation where you are troubleshooting a problem somewhere on a network.

Over the next several pages of this Network+ certification course, you will learn about each of these tools in depth. We encourage you to try out the tool on your own computer as you study.