Troubleshooting Cmd Tools with Switches/Options

Question 1

Ifconfig

Answer 1

Displays basic TCP/IP information and network information, including MAC address of the NIC

Question 2

ifconfig -a

Answer 2

Displays TCP/IP information associated with every interface on a Linux device; can be used with other parameters (see Figure 3-26)

Question 3

ifconfig down

Answer 3

Marks the interface, or network connection, as unavailable to the network

Question 4

ifconfig up

Answer 4

Reinitializes the interface after it has been taken down (via the ifconfig
down command), so that it is once again available to the network

Question 5

man ifconfig

Answer 5

Displays the manual pages, called man pages, for the ifconfig command, which tells you how to use the command and about command parameters (similar to the ipconfig /? command in Windows)

Question 6

dig google.com

Answer 6

Performs a DNS lookup on a domain name

Question 7

dig @8.8.8.8 google.com

Answer 7

Specifies a name server in the google.com domain

Question 8

dig @8.8.8.8 google.com MX

Answer 8

Requests a list of all A records in the google.com domain on a specific name server

Question 9

dig google.com ANY

Answer 9

Requests a list of all record types in the google.com domain

Question 10

dig –x 74.125.21.102

Answer 10

Performs a reverse lookup on a Google I P address

Question 11

man dig

Answer 11

Displays the man page for the dig command

Question 12

Netstat

Answer 12

Lists all active TCP/IP connections on the local machine, including the Transport layer protocol used, messages sent, and received, IP address, and state of those connections

Question 13

netstat -n

Answer 13

Lists current connections, including IP addresses and ports

Question 14

netstat -f

Answer 14

Lists current connections, including IP addresses, ports, and FQDNs

Question 15

netstat -a

Answer 15

Lists all current TCP connections and all listening TCP and UDP ports

Question 16

netstat -e

Answer 16

Displays statistics about messages sent over a network interface, including errors and discards

Question 17

netstat -s

Answer 17

Displays statistics about each message transmitted by a host, separated according to protocol type (TCP, UDP, IP, or ICMP)

Question 18

netstat -r

Answer 18

Displays routing table information

Question 19

netstat -o

Answer 19

Lists the PID (process identifier) for each process using a connection and information about the connection

Question 20

netstat -b

Answer 20

Lists the name of each process using a connection and information about that connection

Question 21

pathping -n google.com

Answer 21

Instructs the command to not resolve IP addresses to host names

Question 22

pathping -h 12 google.com

Answer 22

Specifies the maximum number of hops these messages should take when attempting to reach a host

Question 23

pathping -p 2000 google.com

Answer 23

Identifies the wait time between pings

Question 24

pathping -q 4 google.com

Answer 24

Limits the number of queries per hop; must be followed by a variable to indicate the number of queries allowed

Question 25

tcpdump not port 22 or | tcpdump no port 23

Answer 25

Filters out SSH or Telnet packets, which is helpful when running tcpdump on a remotely access network device

Question 26

tcpdump -n

Answer 26

Instructs the command to not resolve IP addresses to host names

Question 27

tcpdump –c 50

Answer 27

Limits the number of captured packets to 50

Question 28

tcpdump -i any

Answer 28

Listens to all network interfaces on a device

Question 29

tcpdump -D

Answer 29

Lists all interfaces available for capture

Question 30

tcpdump port http

Answer 30

Filters out all traffic except HTTP

Question 31

tcpdump -w capture.cap

Answer 31

Saves the file output to a file named capture.cap

Question 32

tcpdump -r capture.cap

Answer 32

Reads the file capture.cap and outputs the data in the terminal window

Question 33

Unused physical and virtual ports on switches and other network devices should be disabled

Answer 33

Use the shutdown command on Cisco, Huawei, and Arista routers and switches; Use the no shutdown command to enable them again

Question 34

Another Cisco command (also used on Arista devices) to secure switch access ports

Answer 34

Switchport port-security (or just port-security on Huawei switches); Essentially a MAC filtering functions that also protects against MAC flooding

Question 35

Switchport security on a Juniper switch

Answer 35

The mac-limit command restricts the number of MAC addresses allowed in the MAC address table; Allowed MAC addresses are configured with the allowed-mac command

Question 36

Newer versions of Linux

Answer 36

/var/log/messages

Question 37

Older versions of UNIX

Answer 37

/var/log/syslog

Question 38

Solaris versions of UNIX

Answer 38

var/adm/messages