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