Network Tools | CompTIA Network+ N10-007 | 5.2

In this video you will learn about various hardware and software networking tools in addition to various command line interface tools.

Hardware Tools

Crimper

A crimping tool is a device used to conjoin two pieces of metal by deforming one or both of them to hold each other.  The result of the tool’s work is called a crimp.  A crimper attaches a connector to the end of raw twisted pair (TP) or coaxial cable.  If you are working with TP, you need an RJ45 crimping tool (which often also works with RJ11 telephone cable).  After untwisting the wire pairs & aligning them according to the appropriate standard (typically T568B), insert them into an RJ45 connector and push the cable & connector assembly into the crimper.  Line up the crimper jaw with the recessed area of the connector and squeeze.

Cable Tester

A cable tester is an electronic device used to verify the electrical connections in a signal cable or other wired assembly.  Basic cable testers are continuity testers that verify the existence of a conductive path between ends of the cable, and verify the correct wiring of connectors on the cable.  More advanced cable testers can measure the signal transmission properties of the cable such as its resistance, signal attenuation, noise & interference.  Cable testers include a LAN testing unit that can be plugged into a port on the patch panel & a terminator that can be plugged into the other end of the cable into the corresponding RJ45 jack.  This tool tests each wire in the cable and makes sure everything is wired properly.

Punchdown Tool

A punchdown tool is a small hand tool used by network technicians to insert wire into insulation displacement connectors, patch panels, or punch down blocks.  A punchdown tool punches individual wires down into the 110 IDC clips of an RJ45 jack and the patch panel.  The “punching down” of the wires is the actual termination.  The patch cables connect the various ports of the patch panel to a switch and the RJ45 jacks to the computers.

OTDR (Optical Time-Domain Reflectometer)

An OTDR is a device used to precisely detect faults in an optical fiber link of a communication network.  An OTDR simply generates a pulse inside a fiber to be tested for faults or defects.  Pulses are returned to the OTDR and their strengths are then measured and calculated as a function of time and plotted as a function of fiber stretch.  The strength and returned signal tell about the location and intensity of the fault present.^[1]

Light Meter

A light meter is a low cost way to certify optical fiber by measuring fiber optic light continuity, loss & the actual strength of the optical signal.  In fiber optics when a beam of light which carries a signal goes through the optical fiber, the strength of that light beam will diminish over distance.  This means the signal strength becomes weaker.  This loss of light power will affect the fiber optic network in a negative way.  The loss of light power or attenuation of the optical fiber is caused by two issues, scattering and absorption of the light source.  If the degradation is too great then performance of the network will be affected.  Potential causes of signal loss include the following:

• Tight bends in the cable
• Dirty or improperly cleaned connectors
• Too much stress on the cable during installation
• Poorly installed connectors
• Improper splicing technique
• Poor cable quality

Tone Generator & Probe

A tone generator & probe kit is an excellent tool for finding individual phone lines and it consists of two components:

• Tone Device:  Connects to one end of the network cable and sends a tone along the length of the cable.
• Probing Device:  Also known as an inductive amplifier, can pick up the tone anywhere along the cable length and at the termination point.

Loopback Adapter

A loopback adapter (also known as a loopback plug) is a connector used for diagnosing transmission problems.  It plugs into an Ethernet (RJ45) or serial port and crosses over the transmit line to the receive line so that outgoing signals can be redirected back into the computer for testing to verify whether the network adapter & TCP/IP are functioning properly.

Multimeter

A multimeter (multitester) is an electronic measuring instrument that combines several measurement functions in one unit.  A typical multimeter can measure voltage, current, and resistance.  Analog multimeters use a microammeter with a moving pointer to display readings.  Digital multimeters (the most common in use today) have a numeric display, and may also show a graphical bar representing the measured value.  Multimeters can be used for testing both coaxial and TP cabling as well as AC & DC voltages to test computer power supplies and AC adapters.  All multimeters have standard red and black test leads.  When used for voltage tests, the red lead is attached to the power source to be measured, and the black lead is attached to ground.

Spectrum Analyzer

A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument.  The primary use is to measure the power of the spectrum of known and unknown signals.  The input signal that most common spectrum analyzers measure is electrical; however, spectral compositions of other signals, such as acoustic pressure waves and optical light waves, can be considered through the use of an appropriate transducer.  Spectrum analyzers for other types of signals also exist, such as optical spectrum analyzers which use direct optical techniques such as a monochromator to make measurements.  By analyzing the spectra of electrical signals, dominant frequency, power, distortion, harmonics, bandwidth, and other spectral components of a signal can be observed that are not easily detectable in time domain waveforms.  These parameters are useful in the characterization of electronic devices, such as wireless transmitters.  The display of a spectrum analyzer has frequency on the horizontal axis and the amplitude displayed on the vertical axis.  To the casual observer, a spectrum analyzer looks like an oscilloscope and, in fact, some lab instruments can function either as an oscilloscope or a spectrum analyzer.

Software Tools

Packet Sniffer

A packet sniffer is a computer program or computer hardware such as a packet capture appliance that can intercept and log traffic that passes over a computer network or part of a network.^[2]  Packet capture is the process of intercepting and logging traffic.  As data streams flow across the network, the analyzer captures each packet and, if needed, decodes the packet’s raw data, showing the values of various fields in the packet, and analyzes its content according to appropriate specifications.

Port Scanner

A port scan is a process that sends client requests to a range of server port addresses on a host, with the goal of finding an active port; this is not a nefarious process in and of itself.^[3]  The majority of uses of a port scan are not attacks, but rather simple probes to determine services available on a remote machine.  A port scanner is an application designed to probe a server or host for open ports.  Such an application may be used by administrators to verify security policies of their networks and by attackers to identify network services running on a host and exploit vulnerabilities.

Protocol Analyzer

A protocol analyzer is a tool (hardware or software) used to capture and analyze signals and data traffic over a communication channel.  Protocol analyzers work by capturing data across a communication bus in embedded systems.  With the help of protocol analyzers, engineers and developers can design, debug and test their designs through the entire development life cycle of a hardware product.  Quite often, protocol analyzers are used for analyzing network traffic on LAN, PAN, and even wireless networks.  With the help of protocol analyzers, data can be monitored and decoded and the captured data can then be interpreted to generate actionable reports and useful information for network system administrators.^[4]

WiFi Analyzer

A WiFi analyzer allows for you to analyze both 2.4GHz and 5.0GHz wireless networks in the area.  Wireless networks use specific channels within the wireless spectrum.  An overcrowded wireless channel results in decreased bandwidth and/or connectivity issues for your network.  You can use a WiFi analyzer to see what channels are in use and to identify the best channel to set on your router.  A WiFi analyzer can be a standalone device, a program for a desktop computer, or an app on a smartphone.

Bandwidth Speed Tester

Most cable ISPs do not have data caps.  To determine the actual upstream/downstream speeds your connection achieves with an ISP, use a speed-testing website.  Many ISPs provide speed-testing web page links on their customer service pages.  Upstream (uploading) refers to data, page requests, email, and so on being sent from your computer or network to the Internet.  Downstream (downloading) refers to any information being received from the Internet.

Command Line

• ping:  sends IP packets to check network connectivity
• tracert:  similar to PING but returns path information to an IP address destination; in macOS & Linux the command is traceroute
• nslookup:  gathers the network’s DNS (domain name system/server) information
• ipconfig:  displays TCP/IP network information on a computer; in macOS & Linux the command is ifconfig
• iptables:  Linux command to put rules in place for packet filtering for the Linux kernel firewall
• netstat:  displays a list of active TCP connections on a local network
• tcpdump:  a data-network packet analyzer computer program that runs under a command line interface (CLI).  Displays TCP/IP & other packets being transmitted or received over a network to which the computer is attached.
• pathping:  used to combine the functionality of ping & tracert.  It is used to locate spots that have network latency & network loss.
• nmap:  used to discover hosts, services, & operation system detection on computer networks by sending packets and analyzing the responses
• route:  allows you to make manual entries into network routing tables.  It distinguishes between routes to hosts and routes to networks by interpreting the network address of the destination variable, which can be specified either by symbolic name or numeric address.
• arp:  displays & modifies entries in the Address Resolution Protocol (ARP) cache.  The ARP cache contains one or more tables that are used to store IP addresses & their resolved Ethernet or token ring physical addresses.
• dig:  performs DNS lookups & displays the answers that are returned from the queried name server(s).

References

1. Optical Time Domain Reflectometer (OTDR). Techopedia.
2. Connolly, K. (2003). Law of Internet Security and Privacy.
3. RFC 2828 Internet Security Glossary
4. What is a Protocol Analyzer? Total Phase.