Top 50 🔥 Network Administrator Interview Questions and Answers

hi everyone in this video i'm going to show you the top 50 network administrator interview questions and answers my name is lauren and this channel is all about showing you how to become a highly paid itpro fast let's get started [Music] question number one what is a firewall a firewall prevents connection between two or more sources it basically blocks any incoming or outgoing traffic firewalls come in two forms software or hardware firewalls question number two can you explain the difference between http and https protocols http stands for hypertext transfer protocol and is used by the majority of websites as a means of transmitting website data and it allows for the use of hyperlinks this protocol uses tcp port 80. https is a secure version of the http protocol that allows for identity verification and low level encryption using tc port 443 question number three what is a vpn a vpn is a virtual private network it allows users to create a secure connection over public networks such as the internet vpns are commonly used by mobile workers in order to access their company's network from remote locations question number four what are two types of ip addresses and what are they used for all ipv4 ip addresses can be divided into two major groups public and private ip addresses a public ip address is an ip address that is used to access the internet public ip addresses are routed on the internet private internal ip addresses are not routed on the internet and traffic cannot be sent to them from the internet they are only supposed to work within local networks question number five what is dns dns stands for domain name system it is basically the phone book of the internet dns translates domain names for example www.google.com or www.youtube.com to ip addresses so browsers can load those internet resources through the internet protocol question number six what is a default route a default route is a configuration of the internet protocol ip that establishes a forwarding rule for packets when no specific address of a next hop host is available from the routing table or other routing mechanism question number seven what is dhcp and what is it used for dhcp stands for dynamic host configuration protocol and it automatically assigns ip addresses to network devices it completely removes the process of manual allocation of ip addresses and reduces the errors caused due to this question number eight what is dos dos or denial of service attack is an attempt to prevent users from being able to access the internet or any other network services such attacks may come in different forms and are commonly performed by hackers one common method of doing this is to overload a web server so that it can no longer process legitimate traffic any website on this web server then becomes inaccessible question number nine what is network topology network topology is a physical layout of the computer network and it defines how the computers devices cables etc are connected to each other question number 10 what is a router a router is a device that manages the flow of data to multiple connected devices it is a network device that connects two or more network segments it is used to transfer information from the source to the destination in simple words the cable coming from your isp goes into a modem which converts input signals into digital data usable by a computer a router connects your modem with other devices to allow communication between those devices and the internet routers send information in the form of data packets when a router receives a packet it checks its routing table to determine if the destination address is for a system on one of its attached networks or if the message must be forwarded to another router when packets are forwarded from one router to another router the receiving router reads the network address in the packets and identifies the destination network and repeats the process mentioned above question number 11 what is the osi reference model and how many layers does it have the open system interconnection model is a conceptual reference model that defines how applications communicate with each other within a network it also helps you to understand the relationship between networks and defines the process of communication in a network it has seven layers question number 12 let's say a company is expanding its business to other countries it wants all of its branches to remain connected to its corporate headquarters 24 7. which network technology do you think they should use they should use a wan question number 13 what is a proxy server and how do they protect the computer network all devices on a network have an ip address knowing the exact ip address of a network device can leave that device exposed to an attack proxy servers prevent unauthorized external users from accessing those internal ip addresses it makes the computer network virtually invisible to external users question number 14 what is meant by 127.0.0.1 localhost simply put localhost is the default name used to establish a connection with your own computer using the loopback address network think of loopback as looping back to your own machine the loopback address network has a default ip address of 127.0.0.1 localhost is used to test applications on a local computer when you move to a production or remote server you will change the references from localhost to the domain name you are using the ip address 127.0.0.1 is reserved for loopback or localhost connections these networks are usually reserved for the biggest customers or some of the original members of the internet to identify a connection issue the initial troubleshooting step is to ping the server and check if it is responding 127.0.0.1 and localhost are the same things in most of the computer network question number 15 what is a mac address a mac address is a unique device address given to every network connected hardware unlike ip addresses mac addresses are permanent every network connected device has one and only one mac address mac stands for media access control it is a unique 48-bit serial number burned into the network circuitry of every ethernet and wi-fi device question number 16 what is data encapsulation in a computer network to enable data transmission from one computer to another the network devices send messages in the form of packets these packets are then added with the ip header by the relevant osi reference model layer the data link layer encapsulates each packet in a frame that contains the hardware address of the source and the destination computer if a destination computer is on a remote network then the frames are routed through a gateway or router to the destination computer question number 17 what is ipconfig and ifconfig ipconfig stands for internet protocol configuration and is a command used on microsoft windows to view and configure the network interface the command ipconfig is useful for displaying all tcp ip network information currently available on a network it also helps to modify the dhcp protocol and dns settings ifconfig also known as interface configuration is a command that is used on linux mac and unix operating systems it is used to view and configure the tcp ip network interface parameters from the command line question number 18 what is snmp snmp stands for simple network management protocol it is a protocol used for collecting organizing and exchanging information between network devices snmp is widely used in network management for configuring network devices like switches hubs routers printers and servers question number 19 explain three types of networks based on their sizes the size of a network is defined by the geographic area it covers and the number of computers or network devices within it three types of networks based on their size are local area network lan a network with a minimum of two computers to a maximum of thousands of computers within an office or a building is known as a lan generally it works for a single site where people can share resources like printers data storage and more metropolitan area network man it is larger than a land and used to connect various lands across small regions a city campus of colleges or universities and the like which in turn forms a larger network wide area network when multiple lands and mans connected together form a wan it covers a wider area like a whole country or the world question number 20 define round trip time the time taken for a signal to reach the destination and travel back to the sender with the acknowledgement is termed as round trip time rtt it is also called round trip delay rtd question number 21 what is encryption and decryption encryption is the process of converting transmitted data into a form that cannot be read by any device other than the intended recipient decryption is the process of converting back the encrypted data to its original form an algorithm called a cipher is used in the encryption and decryption process question number 22 mention two important actions performed by a cisco switch it uses the source mac addresses of frames to build and maintain a mac address table it also utilizes the mac address table to forward frames via the destination mac address question number 23 what is a link a link refers to the connectivity between two devices it includes the type of cables and protocols used for one device to be able to communicate with the other question number 24 briefly describe nat nat stands for network address translation this is a protocol that provides a way for multiple computers on a common network to share a single connection to the internet question number 25 what is rip rip short for routing information protocol is used by routers to send data from one network to another it efficiently manages routing data by broadcasting its routing table to all other routers within the network it determines the network distance in units of hops question number 26 you have one 48 port switch with three vlans how many collision domains and how many broadcast domains three broadcast domains and 48 collision domains question number 27 draw a diagram of a network you've worked on and please explain it to me this is one of the most common questions asked in network administrator interviews this question will test your problem solving skills confidence and work experience check out lucidchart's networking diagramming tips and draw simple and complex networks for practice a link to lucidchart's website will be listed in the description area under this video question number 28 what's the most important thing about the osi model the most important factor about the osi model is that we can divide up the protocols into layers another key factor is that the layers of the osi model provide encapsulation and abstraction question number 29 can you name the layers of the osi model physical data link network transport session presentation and application question number 30 why can't mac addresses be used instead of ipv4 or ipv6 for networking unlike ip addresses mac addresses do not specify unique destinations for communication an ip scheme can be used for a group of computers to logically distinguish them as a group via routing tables these groups can be divided into multiple levels so that we don't have to keep track of every single subnet for instance 17.x.x.x is within the apple network using an ip scheme helps apple to keep track of where each of its thousands of subnets is located and how to get to them that's not possible with mac addresses question number 31 explain the difference between a vlan and a subnet do you need a vlan to set up a subnet vlans work at the data link layer they refer to the 802.1q standard using vlans you can give ports a unique mac address table separating them from each other vlans can transport one or more subnets a vlan is used for switch partitioning for example let's assume that you have an eight port switch you can use vlans and assign four ports to one vlan vlan one and four ports to another vlan vlan 2. vlan 1 is totally separated from vlan 2 traffic and vice versa on a logical basis you can get two switches using this technique usually if a switch hasn't seen a mac address it will flood the traffic to all other ports vlans prevent this a subnet is a range of ip addresses determined by part of an address often called network address and a subnet mask netmask in simple words a subnet is a small network composed by a group of ip addresses subnets communicate with each other using routers question number 32 mention some common http status codes 1xx informational responses communicates transfer protocol level information 2xx success indicates that the client's request was accepted successfully 3xx redirection indicates that the client must take some additional action in order to complete their request 4xx client-side error this category of error status codes points the finger at clients 5xx server-side error the server takes responsibility for these error status codes question number 33 what is the smallest ipv4 subnet mask that can be applied to a network containing up to 30 devices if you have a standard slash 24 vlan for users a 30 for point-to-point links and a network of up to 30 devices the smallest ipv4 subnet mask would be a 27 or a subnet mask of 255.255.2 question number 34 what is a packet filter and how does it work a packet filter is used as a firewall technique to control network access by monitoring outgoing and incoming packets packets are checked based on their source and destination ip addresses protocols and ports packet filtering is used for modest security requirements it is used for providing isolation of one subnet from another question number 35 what are the advantages of using a reverse proxy server a reverse proxy server will hide the topology and characteristics of your servers it also helps with load balancing because reverse proxy servers enforce algorithms like round robin weighted round robin and weighted least connections some other advantages include ssl offloading and termination question number 36 can you explain the difference between a router and a gateway gateways are used to regulate traffic between two dissimilar networks while routers regulate traffic between similar networks let's say you have a windows 2000 network which uses tcp ip as its primary protocol you can connect your network with the internet using a router because the internet also uses tcp ip as its primary protocol on the other hand you'd use a gateway to connect a pc network with a 3270 mainframe environment or to connect a windows nt network with a netware network question number 37 what is a default gateway a default gateway serves as an access point for outbound connections to other networks it allows one computer to communicate with another computer on a different network question number 38 can you tell me how dns records work dns records tell the dns server which ip address each domain is associated with it also tells how to handle requests sent to each domain dns records are basically mapping files dns records use specific syntax for its configurations and functions some important dns records are soa start of authority records a address mapping records aaa ip version 6 address records cname canonical name records mx mail exchanger records ns name server records ptr reverse lookup pointer records question number 39 what is the number of network ids in a class c network the number of network id bits in a class c network is 24. the number of possible network ids is 2 raised to 21 or 2 million 97 152 the number of host ids per network id is 2 raised to 8 -2 or 254 question number 40 a user in your company wants to connect two computers for file sharing is it possible to do this without using a hub or router yes you can use a crossover cable in this situation the data transmit pin of one cable is connected to the data receive pin of the other cable and vice versa question number 41 which connection provides a secure cli session with encryption to a cisco switch an ssh connection question number 42 let's say a user opens three browsers on his pc to access www.cisco.com to search for ccna information the cisco web server sends a datagram as a reply to the request from one of the web browsers can you tell which information is used by the tcp ip protocol stack on the user machine to identify which of the three web browsers should receive the reply yes you can use the destination port number question number 43 where are cisco ios debug output messages sent by default they are sent to the console line question number 44 let's say a network administrator issues a copy running dash config startup dash config command after making configuration changes on a cisco switch what would be the impact of these commands the new configuration will be loaded if the switch is restarted question number 45 do you contribute to any open source projects contributing to open source projects will help you expand your network and pass a lot of interviews always say yes if it's true when asked this question because the employer would feel that you are enthusiastic about network administration and also willing to share your knowledge contributing to open source projects could be very impactful for your career here are two examples from reddit users to prove that those aren't directly related to network administration but they are meant to prove a point question number 46 tell me about the biggest mistake you've made the interviewer wants to see if you are willing to embrace the fact that we're all fallible be very open and say that you've made mistakes but they have helped you learn a lot and progress in life try to mention a technical mistake in your career instead of a behavioral mistake for example you can say that my biggest mistake was to unplug a server that was running dhcp because of this mistake hundreds of people were not able to access the network for almost 50 minutes question number 47 what technical news sources do you check daily the interviewer wants to gauge your passion for networking just mention your favorite sources a good example could be the cisco networking blog question number 48 tell me about an instance where your team client or boss disagreed with you how did you resolve this situation this is a very common question asked to check your attitude towards disagreement every company wants a person who is open to disagreements and debate this question could be approached in a variety of ways you can talk about a specific instance from your career or life or make up a situation if you have no experience at all to prove that you are a good listener open communicator and know how to analyze the situation question number 49 a network administrator is measuring the transfer of bits across the company backbone for a very important application the administrator notices that the network throughput is lower than the bandwidth expected can you tell which factors could influence the differences in throughput some factors responsible could be the amount of traffic that is currently crossing the network the type of traffic that is crossing the network and the latency that is created by the number of network devices that the data is crossing question number 50 how many hosts are addressable on a network that has a mask of 255.255 6. thanks for watching check out the video on the right for more information to help you develop your i.t career you

Channel: SkillsBuild Training

Views: 14,479

Keywords: network administration, network administrator interview questions and answers, network administrator interview, network admin, administrator, network, network engineer, interview questions and answers, network administrator skills, cisco

Id: hl_hhLvC2Vc

Length: 25min 25sec (1525 seconds)

Published: Wed Mar 24 2021