Networking Tools & Command Line

Question 1

Loopback

Answer 1

Connects transmit pins (or fibers) to receive pins (or fibers) to test a network interface.

Ethernet Pinout:
Pins 1 to 3 = Tx+ to Rx+
Pins 2 to 6 = Tx- to Rx-

Fiber:
Transmit fiber to Receive fiber

Used with diagnostic software to test Ethernet connectivity of a client

Question 2

Cable Certifier

Answer 2

Used with existing cable to determine category or test throughput

Identifies frequency range supported by cable to determine throughput

Can be used to determine length of a cable

Question 3

Butt Set

Answer 3

Test equipment tools used by telephone techs to check for dial tone or verify a call can be placed on the line.

Can connect to a punch-down block to connect to telephone line using alligator clips

Question 4

Throughput Tester

Answer 4

Network appliance that typically has multiple network interfaces can generate high volumes of pseudo-random data for wired/wireless networks.

Used on prototype networks to observe performance under heavy load

Used on production networks to determine throughput of existing network

Question 5

BERT

Answer 5

Bit-Error Rate Tester:
Generates patterns at one end of a link & analyzes the received patterns for errors.

BER is a common measurement for network testing
BER = Bit errors/Bits Transferred

Question 6

Protocol Analyzer/Network Sniffer

Answer 6

Traffic can be captured from the network & reviewed for problems in the communication between devices

Standalone device or software
(Wireshark, Ethereal)

Question 7

Looking Glass Sites

Answer 7

Allows users to connect to view the routing info from a server’s perspective

Useful with BGP router configuration

Question 8

Windows CMD & Bash: arp

Answer 8

Shows MAC address for a known IP address

arp -a
Displays current ARP table on computer

arp -d 192.168.1.1
Deletes ARP mapping for specified IP

arp -s 192.168.1.1 00-AA-BB-4F-5C-23
Adds static ARP entry to force IP to resolve to MAC provided

Question 9

Windows CMD: Ping

Answer 9

Checks IP connectivity between devices

ping www.diontraining.com
Stops pinging after 4 pings

ping -n 10 www.diontraining.com
Ping 10 times, then stop

Ping -t www.google.com
Ping forever (until CTRL+C)

Ping -6 www.google.com
Ping using IPv6

Question 10

Windows CMD: nbtstat

Answer 10

Displays NetBIOS info for IP-based networks
Displays a listing of NetBIOS device names learned by the PC

nbtstat -a
Displays the NetBIOS table of the remote PC provided

nbtstat -c
Displays PC’s NetBIOS name cache on local computer

Question 11

Windows CMD & Bash: netstat

Answer 11

netstat -a
Displays all connections & listening ports

netstat -n
Displays addresses & port numbers in numerical form

netstat -s
Displays stats for connections by protocol type
(IPv4, IPv6, TCP, UDP, ICMP)

Question 12

Windows CMD: route

Answer 12

Used to change or display contents of PC’s IP routing table

route print
Displays contents of the IP routing table

route delete 192.168.1.1
Deletes entry from routing table

route add 192.168.1.1 192.168.2.1
Adds routing from first IP to second IP

Question 13

Bash: ifconfig & ip

Answer 13

Same as ipconfig in Windows

ifconfig -a (Provides additional info)
ifconfig down = turn off NIC
ifconfig up = turn on NIC

ip
Assigns an address to a network interface or configures network interface
parameters

Question 14

Bash: ping

Answer 14

Similar to Windows, runs forever by default

ping -c 10 www.google.com
Pings 10 times, then stops

ping -6 www.google.com
Ping using IPv6

Question 15

Bash: nslookup & host

Answer 15

nslookup = Same as Windows

host www.google.com
Works like nslookup, except only provides a single line response with the address

Question 16

Bash: Dig

Answer 16

Resolves a FQDN to an IP address
More info than nslookup
No interactive mode

Dig -t mx google.com
Looks up mail records (mx) for google.com

Question 17

Bash: route

Answer 17

Used to change/display contents of PC’s current IP routing table

route
Displays contents of IP routing table

route -n
Displays the content of IP routing table, including default gateway

Question 18

Packet Capturing

Answer 18

Used to capture packets running over a network connection in real time
and then save them for later analysis

Ex: SolarWinds, Ethereal, Netasyst, tcpdump, WinDump

Question 19

Bandwidth Speed Test

Answer 19

Verifies the real-world throughput from a client device all the way out to the Internet and back

Question 20

Port Scanner

Answer 20

Determines which ports are open on a network

Question 21

iPerf

Answer 21

Gathers an active measurement of the maximum achievable bandwidth on an IP-based network

Question 22

NetFlow Analyzer

Answer 22

Performs monitoring, troubleshooting and in-depth inspection, interpretation, and synthesis of traffic flow data

Question 23

IP Scanner

Answer 23

Used to search for and detect IP addresses and other information related to devices on the network

Question 24

hostname Command

Answer 24

Used to display the hostname portion of the full computer name for a given system

Question 25

tcpdump Command

Answer 25

Allows for the display of TCP/IP and other packets being transmitted or received over a network to the client’s screen

Question 26

nmap Command (Network Mapper)

Answer 26

Discovers hosts and services on a computer network by sending packets and analyzing the responses

Question 27

Network Platform Commands: Show Interface

Answer 27

Displays statistics for the network interfaces on the device

Cisco: show interface
Juniper: show interfaces
PoE+ Sidewinder: cf interface

Question 28

Network Platform Commands: Show Config

Answer 28

Displays the current system configuration on the screen

Cisco: show config
Juniper: show configuration
PoE+ Sidewinder: cf config

Question 29

Network Platform Commands: Show Route

Answer 29

Displays the current state of the routing table on the device

Cisco: show route
Juniper: show route
PoE+ Sidewinder: cf route status