Top 180 Networking Interview Questions for Beginners

by | Sep 27, 2017 | Free Resources

Ultimate List Networking Interview Questions for Beginners & Freshers

networking interview questions

Question 1:- What are the different network stack models and list all the layers of OSI model?

Question 2:- What are the functions of Trasport, Network, and Datalink layers?

Question 3:-  What are the different protocols work at each of the layers?

Question 4:- What is end to end communication and Hop to Hop communication?

Question 5:- What is a port number and give some examples.

Question 6:- Explain IP layer ( L3) and IP protocol header.

Question 7:- What is fragmentation and explain how IP will handle the fragmentation.

Question 8:- What is the difference between Half-duplex and Full-duplex?

Question 9:- Define Unicast, Multicast and Broadcast. What is the use of Multicast?

Question 10:-What are the functions of Data link layer, what is the MAC format?

Question 11:- What is a Frame, explain the frame header.

Question 12:- A scenario to explain the packet flow layer wise.

Question 13:- What is IP address and it’s format.

Question 14:- What are the different Classes of IP address and give the range of each class.

Question 15:- What is network id , broadcast id and subnet mask?

Question 16:- How to find the netsork id of a given IP address?

Question 17:- What is subnetting and give us a scenario for implementing IP subnetting, a task on subnetting.

Question 18:- What is the difference between FLSM and VLSM?

Question 19:- What is the subnetwork address if the destination address is and the subnet mask is

Question 20:- What is the subnetwork address if the destination address is and the mask is

Question 21:- A company is granted the site address (class C).

Question 22:- The company needs six subnets. Design the subnets.

Question 23:- A company is granted the site address (class B). The company needs 1000 subnets. Design the subnets

Question 24:- You want to implement class c IP addresses in your, what subnet mask you should implement in your network so that number of subnets will be equal to the number of hosts per subnet

Question 25:-ARP works at which layer and Why?

Question 26:- Is ARP part of the Ethernet frame?

Question 27:- What is the target IP address in ARP request and ARP reply packet?

Question 28:- What is GARP and how it will be useful?

Question 29:- Difference between ARP and GARP?

Question 30:-What is the target IP address in GARP request and GARP reply packet?

Question 31:- Packet structure of ARP and GARP?

Question 32:- Explain various ICMP messages?

Question 33:- Which ICMP message confirms the traceroute is completed?

Question 34:- Which is the importance of identification field in the IP packet?

Question 35:- Why fragmentation is required?

Question 36:- Which device can reassemble the packet?

Question 37:- How the packet is reassembled?

Question 38:- What is the importance of DF, MF flag?

Question 39:- What is the purpose of fragment offset?

Question 40:- What is the importance of TTL value?

Question 41:- What does the protocol field determines in the IP packet?

Question 42:- Explain 3 way handshake process?

Question 43:- What is the importance of sequence number?

Question 44:- How sequence number is calculated?

Question 45:- What is the purpose of acknowledgement number?

Question 46:- What is the difference between Total length and header length?

Question 47:- What does window size indicate?

Question 48:- When the MSS value is getting negotiated?

Question 49:- Explain the control flag?

Question 50:- What is the difference between PUSH and URG flag?

Question 51:- What is the purpose of RST bit?

Question 52:- What is SACK?

Question 53:- Who is responsible for the reliability of UDP packet.

Question 54:- Difference between TCP and UDP.

Question 55:- In a serialized connected network including Router, Switches and Firewall with varied MTU sizes Which device will fragment the packet and what are the sizes of each fragment?

Question 56:- Why Firewall reassembles the packet?

Question 57:- What Firewall verifies after reassembling the packet?

Question 58:- Can reassembly done by intermediate device?

Question 59:- Is fragmentation applicable only for TCP?

Question 60:- Can we fragment packet containing UDP data?

Question 61:- What is the difference between Active and Passive FTP?

Question 62:-What is the important of port command?

Question 63:- Which FTP type is preferred if firewall is blocking the connection?

Question 64:- How active FTP works?

Question 65:- How passive FTP works?

Question 66:- How TFTP works? Explain the protocols involved.

Question 67:- What is SNMP?

Question 68:- SNMP versions.

Question 69:- Components of SNMP?

Question 70:- Ports used in SNMP?

Question 71:- Explain MIB?

Question 72:- Explain how to implement SNMP on a network?

Question 73:- Explain difference between SNMP Query response & SNMP trap?

Question 74:-What are the various instances of getting “Request timed out”?

Question 75:- Difference between destination host unreachable and destination network unreachable?

Question 76:- Explain various ICMP messages?

Question 77:- How traceroute works?

Question 78:- What is the difference between traceroute and tracert?

Question 79:- Is traceroute a reliable tool to identify network issues?

Question 80:- Why there are three columns in traceroute results?

Question 81:-Which ICMP message confirms the traceroute is completed?

Question 82:-What does * indicate in traceroute result?

Question 83:- Difference between HTTP & HTTP/S?

Question 84:-How DHCP works?

Question 85:-What is the reason for getting APIPA address?

Question 86:- How to troubleshoot APIPA issue?

Question 87:- What is the purpose of relay agent?

Question 88:- Is DHCP decline message is sent by Client or Server?

Question 89:- Is DHCPNACK message is sent by Client or server?

Question 90:- How DHCP discover message is being forwarded by router when it is a broadcast message?

Question 91:- Explain zone transfer?

Question 92:- What are the types of records?

Question 93:- What is forward lookup & Reverse lookup?

Question 94:- When will DNS use TCP?

Question 95:- When will DNS use UDP?

Question 96:- Explain DNS quesr process.

Question 97:- Explain Auto negotiation.

Question 98:- What is MDI & MDIX ports?

Question 99:- Explain Straight Through & Cross Over cabling. Where will it be used.

Question 100:- What is inter vlan routing?

Question 101:- What is sub interface?

Question 102:- What is a broadcast domain and a collision domain

Question 103:- Compare HUB and Switch WRT broadcast and collision domain

Question 104:- What is a MAC address table and how a Switch will build a MAC table, single switch scenario and multiple switch scenario

Question 105:- What is a VLAN and how it will reduce the broadcast traffic

Question 106:- What is the difference between an access port and a trunk port and what are different types of tagging

Question 107:- What is a native VLAN what type of traffic will go through native VLAN

Question 108:- What is STP and why do we need redundant links between switches,

Question 109:- What are the different port states and timers and BPDU

Question 110:- What is bridge id and its format and the Root bridge election criteria

Question 111:- STP convergency with 4 switches, what is the Root port election criteria

Question 112:- What is TCN and TC BPDU and STP reconvergency

Question 113:- Can you explain the ARP Header with the fields?

Question 114:- What are the changes a frame undergoes in a switch

Question 115:- What is a routing table?

Question 116:- Define static routing & dynamic routing?

Question 117:- What is a default route?

Question 118:- What is a route metric?

Question 119:- What is the difference between routing and routed protocol? Give examples.

Question 120:- What is route lookup process, parent and child route

Question 121:- What is the effect of IP classless and classfull on routing

Question 122:- What are the different type of routing table entries and Admin distance

Question 123:- What are the different types of routing protocols and list for each type

Question 124:- What do you understand by backbone area?

Question 125:- What is the need for dividing the autonomous system into various areas?

Question 126:-What is the benefit of dividing the entire network into areas?

Question 127:- What changes it would make if the network is divided or not divided into areas?

Question 128:- What is the purpose of Stub area?

Question 129:- What is the purpose of NSSA area?

Question 130:- How Stub and NSSA works?

Question 131:- What are the criteria to form neighbour ship?

Question 132:- Why master slave needs to be elected between two neighbour interface?

Question 133:- What is virtual link?

Question 134:- Virtual link updates are multicast or unicast?

Question 135:- Explain the various states of OSPF?

Question 136:- What are various LSA and message Types?

Question 137:- What is the difference between E1 an E2 metrics?

Question 138:- Explain router redistribution?

Question 139:- How DR and BDR is elected?

Question 140:- Difference between eBGP and iBGP?

Question 141:- What is the TCP port number for BGP communication?

Question 142:- Explain various states of BGP?

Question 143:- What is the reason for an interface stuck on active state?

Question 144:- Do we need to follow 3 way handshake process to establish BGP communication?

Question 145:- What are various path attributes?

Question 146:- What is difference between Local preference and MED attributes?

Question 147:- Explain the sequence of selecting the best route through the attributes?

Question 148:- There are two PC connected to a switch, assign Ip address and explain how they will communicate for the first time.

Question 149:- Functionality of switch

Question 150:- what is MAC address? physical or logical address?

Question 151:- Difference between broadcast domain and collision domain?

Question 152:- What is Vlan?

Question 153:- what is dot1q?

Question 154:- what is STP, RSTP

Question 155:- Explain L2 loop?

Question 156:- What is ARP, Proxy ARP

Question 157:- Does ARP exceeds its broadcast domain

Question 158:- Explain DORA process with example both i.e server on same network and different network (DHCP imp topic should now in detail that is wireshark details)

Question 159:- Gracious ARP

Question 160:- Ipsec, GRE

Question 161:- what is native vlan

Question 162:- Have you ever connected end user via trunk port to a switch? if yes what is the outcome?

Question 163:- For routing atleast OSPF required, states and LSA

Question 164:-what is the roll of preamble in ethernet header?

Question 165:-Questions 165 What is Etherchannel

Question 166:-Describe Backgroud process of ICMP

Question 167:-what are the different layer of OSI model?

Question 168:- Functionality of different layers?

Question 169:- Difference between TCP and UDP

Question 170:- Different tcp and udp port used for communication name few with port no.

Question 171:- what is PDU?

Question 172:-Difference between icmp and Traceroute?

Question 173:-Expain three way handshake process?

Question 174:-What are TCP flags

Question 175:- What is fastswitching?

Question 176:- what is DNS?

Question 177:- How switch know the MAC address and how it makes its table?

Question 178:-what is root bridge?

Question 179:- conditions to select a root bridge?

Question 180:- What is bpdu guard, root gaurd?


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