Networking Tools & Command Line Flashcards
Loopback
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
Cable Certifier
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
Butt Set
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
Throughput Tester
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
BERT
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
Protocol Analyzer/Network Sniffer
Traffic can be captured from the network & reviewed for problems in the communication between devices
Standalone device or software
(Wireshark, Ethereal)
Looking Glass Sites
Allows users to connect to view the routing info from a server’s perspective
Useful with BGP router configuration
Windows CMD & Bash: arp
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
Windows CMD: Ping
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
Windows CMD: nbtstat
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
Windows CMD & Bash: netstat
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)
Windows CMD: route
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
Bash: ifconfig & ip
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
Bash: ping
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
Bash: nslookup & host
nslookup = Same as Windows
host www.google.com
Works like nslookup, except only provides a single line response with the address
Bash: Dig
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
Bash: route
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
Packet Capturing
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
Bandwidth Speed Test
Verifies the real-world throughput from a client device all the way out to the Internet and back
Port Scanner
Determines which ports are open on a network
iPerf
Gathers an active measurement of the maximum achievable bandwidth on an IP-based network
NetFlow Analyzer
Performs monitoring, troubleshooting and in-depth inspection, interpretation, and synthesis of traffic flow data
IP Scanner
Used to search for and detect IP addresses and other information related to devices on the network
hostname Command
Used to display the hostname portion of the full computer name for a given system
tcpdump Command
Allows for the display of TCP/IP and other packets being transmitted or received over a network to the client’s screen
nmap Command (Network Mapper)
Discovers hosts and services on a computer network by sending packets and analyzing the responses
Network Platform Commands: Show Interface
Displays statistics for the network interfaces on the device
Cisco: show interface
Juniper: show interfaces
PoE+ Sidewinder: cf interface
Network Platform Commands: Show Config
Displays the current system configuration on the screen
Cisco: show config
Juniper: show configuration
PoE+ Sidewinder: cf config
Network Platform Commands: Show Route
Displays the current state of the routing table on the device
Cisco: show route
Juniper: show route
PoE+ Sidewinder: cf route status
