basic network commands & network types

Question 1

one of the most basic tools for testing connectivity to other hosts. It sends an internet control message protocol (ICMP) echo request to a host and listens for the reply. If a reply is received, it will display the time it took and the time to live (TTL) left. has many options for setting attributes of the request, like the maximum TTL, IPv4/IPv6, and the number of requests to send. is useful in troubleshooting connectivity with other devices. If a reply is not received, you will receive a timeout message, which could indicate connectivity issues, firewall issues, or both issues with the other device. In addition, due to the time to get a response, the latency between two devices can be measured, enabling a network engineer to troubleshoot performance problems or a network architect to determine where to place devices to minimize response time to other systems and users.

Answer 1

ping

Question 2

used to trace the route an IP packet takes to a destination. It displays each hop (next router) in a numerical list with the hop’s IP address and the time it takes to receive the packet. The command used to trace the route an IP packet takes to a destination. It displays each hop (next router) in a numerical list with the hop’s IP address and the time it takes to receive the packet. It can be useful in determining where a ping fails, troubleshooting performance issues, and other aspects regarding connectivity.

Answer 2

Traceroute and tracert

Question 3

used for linux systems to trace the route

Answer 3

command traceroute

Question 4

used for windows system to trace the route

Answer 4

tracert

Question 5

it displays the path taken by a packet from its source to its destination. useful because it can be used by any user instead of needing superuser privileges. It is primarily used in Linux.

Answer 5

tracepath

Question 6

provides the user with the IP, subnet mask, and default gateway for each network adapter by default with the /all option information, such as MAC address, DHCP status, and lease information.

Answer 6

ipconfig
The command ipconfig/release can be used to release all connections and renew all adapters. It is primarily used in Windows.

Question 7

used to configure the kernel network interfaces. It is implemented at the time of booting to configure the necessary interfaces. Once the interfaces are configured, it is used for debugging or tuning the system. It is primarily used in Linux.

Answer 7

ifconfig

Question 8

displays the IP to physical (MAC) address mappings for hosts that have been discovered in the ___ cache. can be used to add, remove, or modify entries in the __ cache. The hosts need to be on the local network, as these addresses are discovered by broadcasting to everyone on the network and noting the reply from the owner; broadcast traffic is not allowed through a router so that the system will maintain the MAC address of the router.

Answer 8

ARP (Address Resolution Protocol)

Question 9

displays information about active ports and their state and can be useful in troubleshooting and capacity management. The command ___ -r displays routing information for network adapters. It is available in Windows, MacOS, and Linux.

Answer 9

netstat (network statistics)

Question 10

displays information for displaying DNS information and troubleshooting DNS problems. It is useful in displaying names to IP address mappings.

Answer 10

Nslookup (name server lookup)

Question 11

used to query the DNS name servers. It is helpful in troubleshooting DNS problems. It is also used for lookups and will display answers from the query. It is a replacement for nslookup.

Answer 11

Dig (domain information groper)

Question 12

ool most often used to look up who owns a domain or block of IP addresses on the internet, including name, email address, and physical address. However, there are many privacy options that hide this information from being returned. It is primarily used in Linux.

Answer 12

Whois

Question 13

used to display the current route tables on a host. can also be used to add or remove routes. This is used by the local host to determine where to send traffic (0.0.0.0 means the default gateway, where the router sends things if it is not otherwise defined in the routing table).

Answer 13

route

Question 14

used to securely copy files between servers, leveraging SSH (secure shell) for authentication and encryption.

Answer 14

SCP (Secure Copy Protocol)

Question 15

copies the file from one host to another host. The data is unencrypted. If encryption is needed, FTPS uses SSL/TLS (Secure Sockets Layer, replaced by Transport Layer Security; the same encryption used in https). Transfer uses TCP (transmission control protocol) for reliability and is often used on the internet and other wide-area networks, where errors may be more common.

Answer 15

FTP (file transfer protocol)

Question 16

transfers a file from either a client to a server or from a server to a client using UDP (user datagram protocol) instead of TCP, and so it is usually used on reliable (local) networks.

Answer 16

TFTP (trivial file transfer protocol)

Question 17

displays information about a user or users on a remote system, including things such as last log-in time and username. It is primarily used in Linux.

Answer 17

finger

Question 18

scans networks to see what it can find in terms of hosts and open ports (including well-known ones for many applications). It is commonly used to determine what is deployed on a network for vulnerability analysis, security scans, and related activities. Nmap is not native to either Linux or Windows but can be downloaded for free and used with both.

Answer 18

Nmap (Network Mapper)

Question 19

displays TCP/IP packets and other network packets that are being transmitted over the network system. It is a form of protocol analyzer (sometimes called a sniffer) and is designed to show the contents of network packets in human-readable form for troubleshooting, security analysis, etc. is not native to either Linux or Windows but can be downloaded for free and used with both.

Answer 19

Tcpdump

Question 20

allow a user to manage accounts and devices remotely. The main difference between the two is that SSH is encrypted, and thus all data is secure from eavesdropping, while telnet is unencrypted.

Answer 20

Telnet and SSH (secure shell)

Question 21

An organization needs to perform an analysis to identify vulnerabilities such as open firewall ports, unauthorized operating systems or device types, and weak passwords. Which tool is recommended?

Answer 21

nmap
can perform many types of vulnerability scans by sending specially crafted data packets and learning about the target(s) based on the responses of the target(s).

Question 22

A server administrator is tasked to harden the database servers, and one of the requirements is to document any firewall ports that are open and closed. Which native Windows command line utility should the administrator use?

Answer 22

netstat

Question 23

Which command should be run in Linux to ping an IP address 192.168.0.15 eight times before it automatically terminates the process?

Answer 23

ping -c 8 192.168.0.15
The -c switch is used in Linux to limits the number of pings within a single session. In this example, the ping command attempts transmission eight times and is the correct answer.

Question 24

is a network that is centered around a person and their devices. allows for various devices, such as a person’s desktop computer, laptop, smartphone, tablet, headphones, wireless keyboard and mouse, and speakers to communicate with each other, often over Bluetooth in the case of wireless connections or USB in the case of wired connections. can be used to enable communication between the devices, such as a device sending music to speakers or headphones, or can be used as a jumping-off point for other devices to a network gateway, such as when a mobile phone acts as a Wi-Fi hotspot for other devices.

Answer 24

personal area network, or PAN

Question 25

consists of computers connected within a limited area. Some examples are a home, lab, or office building. Most often, use Ethernet, Wi-Fi, or both to connect the network devices. Many are wireless, where users are connected via Wi-Fi and can move unrestricted throughout the coverage area. This is a popular choice for home users and small businesses, as it is easy and inexpensive to install and allows guests to use the network as well.

Answer 25

local area network, or LAN

Question 26

is a LAN with wireless connectivity. Unlike LANs, which are wired, ___ use Wi-Fi to communicate with devices. Users and devices can be placed anywhere and move anywhere in the coverage area. This is a popular choice for small businesses, as it is easy and inexpensive to install and allows guests to use the network as well with a hotspot service. Many also act as a gateway to the internet for users.

Many private homes use it in the form of Wi-Fi, as it allows for multiple users to be connected to the network (and usually the broader internet), but not be tied down to a specific location in the home.

Answer 26

wireless local area network, or WLAN

Question 27

is a network that allows access to storage devices specifically instead of the more general networking that can be used for any purpose. allow servers to access devices such as tape libraries and disk arrays while presenting them to the operating system like any other locally attached device.

Typically, is a network dedicated to storage devices and the servers that need access to them. The key reason for this is to reduce interference from normal LAN traffic during data transfer. may also use other protocols, such as Fibre Channels that do not usually operate on traditional network equipment.

Answer 27

storage area network, or SAN

Question 28

provides networking of multiple LANs across a limited area, like a university campus or a group of buildings owned by a company. Each LAN would typically be constrained to a single building (or even just a part of a building), and the ___ would link them together in much the same way that a WAN (wide area network, which will be defined later) does but over a smaller geographic area. typically connects LANs owned by a single company, university, government agency, etc.

Answer 28

campus area network, or CAN

Question 29

provides networking across a larger area than a CAN, but smaller than a WAN, such as a whole city or the equivalent of a metropolitan area (hence the name), though it is not necessarily limited by city boundaries. ____ is made up of many LANs and is owned by many organizations, government entities, etc., within the city to create a fabric of network coverage, often at higher speeds than maybe commercially viable when connecting directly to a WAN when connecting to other entities in the same ___. Often, is then connected to a larger WAN (usually the internet) for access beyond the city.

Answer 29

metropolitan area network, or MAN

Question 30

except that it covers a large geographical area within its network. This would be the case for worldwide businesses or government bodies. The internet is an example of a __, as it can connect individual users across the globe. are able to link these smaller networks to transfer data over hundreds of thousands of miles, whereas a true LAN is only able to do so over its small network.

Answer 30

wide area network, or WAN
For example, banks use private WANs to connect hundreds of branches across the nation. This allows their sensitive user information to be passed from branch to branch without compromising security or traveling over a public network like the internet. Because of this, a banking customer can go to any branch across a country and have access to their accounts and funds.

In contrast to the above types of networking, there are two other ways of looking at networks: they are defined by who has the resources and who needs access to them.

Question 31

there is a distinct server and a distinct client. The server is the system that stores data and information. The client is the machine that needs access to that data. This is the traditional model of networking since the 1990s

Answer 31

client-server network model