Network+ 5.2

Identify the problem

- Gather information Was it functioning? When was the last time? - Duplicate the problem, if possible If you can duplicate then you can begin solving - Question users Talk to user after making initial assessment of the problem is complete - Identify symptoms Write down the symptoms for future reference - Determine if anything has changed What exactly did change? Software or hardware? - Approach multiple problems individually Focus on one problem at a change to see if changes you are implementing are working

ifconfig

A TCP/IP configuration and management utility used with UNIX and Linux systems.

Packet sniffer

A device or program that monitors the data traveling between computers on a network.

Nmap

A network utility designed to scan a network and create a map. Frequently used as a vulnerability scanner. -Port scan - Find devices and identify open ports -Operating system scan -Discover the OS without logging in to a device -Service scan -What service is available on a device?

Tone generator

A small electronic device that issues a signal on a wire pair. When used in conjunction with a tone locator, it can help locate the termination of a wire pair.

Spectrum analyzer

A software tool that assesses the characteristics of wireless signals. (for example, frequency, amplitude, and the effects of interference)

cable tester

A tool for testing if a cable can connect properly end-to-end and to determine if a cable has a short.

punchdown tool

A tool used to punch individual wires from a network cable into their slots to terminate the cable.

Multimeter

An instrument for measuring the properties of an electrical circuit.

pathping <ip address>

Combination of ping and traceroute

netstat -n

Do not resolve names

ipconfig /all

Enables the MAC address information to be displayed from the command prompt

ipconfig /flushdns

Flush the DNS resolver cache

Protocol analyzer

Hardware or software that captures packets to decode and analyze their contents.

nslookup <ip address>

Lookup hostname from DNS server using IP address

OTDR

Optical Time Domain Reflectometer A performance testing device for use with fiber-optic networks. It works by issuing a light-based signal on a fiber-optic cable and measuring the way in which the signal bounces back.

ping -t <ip address>

Ping until stopped with Ctrl-c

Loopback adapter

Plugs into a port and crosses over the transmit line to the receive line so that outgoing signals can be redirected into the computer for testing.

ipconfig /release

Release the DHCP lease

ipconfig /renew

Renew the DHCP lease

ping -a <ip address>

Resolve address to a hostname

ping -n <count> <ip address>

Send # of echo requests

ping -f <ip address>

Send with Don't Fragment flag set

netstat -b

Show binaries

Port scanner

Software to search a system for any port vulnerabilities.

ping <ip address>

Test reachability to a TCP/IP address

ipconfig

The utility used to display TCP/IP addressing and domain name information in the Windows client operating systems.

WiFi analyzer

Tool for checking/diagnosing issues on a wireless network.

Crimper

Used to attach a connector (for example, an RJ-45 connector) to the end of an unshielded twisted-pair (UTP) cable.

route print

Windows command to view the routing table.

light meter

a device to measure light intensity

arp -a

command prompt that will show IP addresses and corresponding MAC addresses of remote computers.

traceroute <ip address>

displays the network path to a given destination

netstat -a

shows in depth TCP and UDP connections