Network Essential Interview Questions
Network Essential Interview Questions
Network Essential Interview Questions
Ans- A group of devices which are connected to each other through some media
is called a network. LAN, MAN and WAN are the types of network.
5. What is URL?
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Ans- URL stands for Uniform Resource Locator, and is used to specify addresses
on the World Wide Web.
Ans- Open System Interconnection is a logical layered model which describes the flow of data
from sender to receiver device. It has 7 logical layers and each layer perform specific task on
the data. OSI was developed by ISO (International Standard for Standardization)
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7- What are the different types of Network Cables?
Attenuation- As the signals travel through cables, they lose their strength. This
loss of signal is called attenuation.
Category Characteristic
Cat5 It provides 100 Mbps of Bandwidth and the signal frequency is
100 MHz
Cat5e It provides 1000 Mbps of Bandwidth and the signal frequency is
100 MHz
Cat6 It provides 1000 Mbps of Bandwidth and the signal frequency is
250 MHz
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10- Explain the UTP/STP network cable color coding according to…………..
11- How to create cross and straight cables? What is the use of cross and
straight cable?
Ans-
Cross T-568A-----------------------------------------T568B
Straight T-568B-----------------------------------------T568B
Cross cable is use to connect similar devices whereas Straight cable is use to
connect dissimilar devices.
12- What is MAC address? How to check the MAC address of the PC?
Ans- MAC address is the physical address of the device which is 48-bits (6-Byte)
address. Ipconfig /all or getmac command is use to check the MAC address of the
computer.
13- Define Hub, Repeater, Switch, Router and Gateway? Tell me the OSI layer
of each device?
Hub: - A hub operates at the physical layer of OSI model. It connects multiple
devices together in a single network segment. A hub also called multiport
repeater. It operates in half duplex mode and doesn’t provide guaranteed
bandwidth to the connected device.
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Switch: - A Switch operates of the Data link layer of OSI model. It connects
multiple devices together in a single network segment. It is called an intelligent
network device because it creates own MAC address table to forward the
frame to the appropriate destination. It operates in full duplex mode and
provides guaranteed bandwidth to the connected device.
14- What is Topology? Define Bus, Star, Ring, Mesh, Tree and Hybrid
topology?
Star Topology: - In star topology multiple devices are connected to a centralized device such as
Hub or switch.
Ring Topology: - In ring topology multiple devices are connected in a physical loop in point-to-
point manner.
Mesh Topology: - In mesh topology all the devices are connected to each other through a
dedicated link.
Tree Topology: - In tree topology multiple star topologies are connected to a centralized bus
topology.
Ans-
Class Range
A 0-127
B 128-191
C 192-223
D 224-239
E 240-255
18- What is Subnet Mask? What is the default subnet mask of class A, B and
C?
Ans- A subnet mask is a 32-bit number used to differentiate the network component of an IP
address by dividing the IP address into a network address and host address.
A- 255.0.0.0
B- 255.255.0.0
C- 255.255.255.0
19- What is the difference between private and public IP address? What is
private IP address range in class A, B and C?
Class Private IP
A 10.0.0.0 to 10.255.255.255
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B 172.16.0.0 to 172.31.255.255
C 192.168.0.0 to 192.168.255.255
Ans- When a device is assigned a static IP address, it does not change. The device
always has the same IP address. Dynamic IP addresses are assigned by the DHCP
Server when they connect. These IP addresses are temporary, and can change
over time.
IPV4 IPV6
It is 32-bits address. It is 128-bits address.
32-bits are divided into 4 equal parts; each part is 128-bits are divided into 8 groups; each group is having
having 8-bits and called an octet. 16-bits and called a block.
Octets are separated by. (dot) Blocks are separated by : (colon)
IPV4 is written in decimal format. IPV is written in Hexadecimal format.
It uses subnet mask to determine network and host It uses prefix to determine network and host bits.
bits.
It is divided into 5 different classes. No classification.
There are 3 types of address Unicast, Multicast and There are 3 types of address Unicast, Multicast and
Broadcast. Anycast.
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24- What are the layers of TCP/IP model?
TCP UDP
Transmission Control Protocol User Datagram Protocol
TCP is a connection-oriented protocol. UDP is a connectionless protocol.
TCP is reliable UDP is unreliable
TCP is slow UDP is fast
TCP rearranges data packets in the order specified. UDP has no inherent order as all packets are
independent of each other
TCP header size is 20 bytes UDP Header size is 8 bytes.
TCP does error checking UDP does error checking, but no recovery options.
Acknowledgement segments No Acknowledgment
TCP does Flow Control. UDP does not have an option for flow control
FTP- The File Transfer Protocol (FTP) is a standard network protocol used to
transfer computer files from one host to another host over a TCP-based network.
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SMTP- The Simple Mail Transfer Protocol is an application protocol to send mails.
Domain Name System (DNS) server is use to translate Fully Qualified Domain
Names (FQDN) into IP addresses and IP address into Fully Qualified Domain
Name.
Windows Internet Name Service (WINS) is use to resolve NetBIOS name into IP
address.
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29- What is the use of following commands
a. Ping- The Packet Internet Gopher (Ping) command helps to verify IP-
level connectivity. When troubleshooting, you can use ping to send
an ICMP echo request to a target host name or IP address.
b. Ipconfig and Ipconfig /all- These commands are use to verify TCP/IP
Configuration in Windows OS.
c. Ipconfig /release and Ipconfig /renew- /release is used to release
current dynamic IP address whereas /renew is used for request new
IP address.
d. Tracert command can show you the path of packet from your
computer to the Destination. It will list all the routers it passes
through until it reaches its destination.
e. Pathping- The pathping command is a route tracing tool that
combines features of the ping and tracert commands. The pathping
command sends packets to each router on the way to a final
destination over a period of time
f. Arp- Arp command allows you to display and modify the Address
Resolution Protocol (ARP) cache. An ARP cache is a simple mapping
of IP addresses to MAC addresses.
g. Netstat- Netstat command provides information and statistics
about protocols in use and current TCP/IP network connections.
Ans- A network in which devices are connected through Radio Frequency (RF)
signal is called wireless Network. The IEEE standard of wireless is 802.11.
31- What are the differences between wired LAN and wireless LAN?
Wired Wireless
IEEE Standard is 802.3 IEEE standard is 802.11
Devices are physically connected. Devices are logically connected.
Signal loss is low. Signal Loss is high.
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Faster data transmission rate. Slower data transmission speed
More Secure Less Secure
Covers large distance. Covers short distance.
32- Complete the following
Ans- In Ad-hoc network devices are connected in wireless network using their LAN
cards and Access Point or Wireless Router is not required in Ad-Hoc.
Change the default setting of wireless router (IP Address, SSID, Admin
Password etc)
Configure Network Password
Enable encryption
Configure MAC filtering
Disable SSID broadcast
Configure 802.1x
Physical security of Wireless Router/Access Point
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a. SSID- Service Set Identifier is technical term for a wireless network
name. When you set up a wireless network, you give it a name that is
called SSID. SSID is a case sensitive, 32 alphanumeric.
b. Mac Filtering refers to a security access control method whereby the
48-bit address assigned to each network card is used to determine
access to the network.
c. WEP and WPA are the encryption method used in wireless network.
WEP provides 56 or 128-bit encryption whereas WPA provides 256-
bit encryption.
https://www.isat.co.za/support-online/adsl-setup-dlink-2750u-router.aspx
https://www.utilizewindows.com/internet-connection-sharing-ics-configuration-
in-windows-7/
http://www.youngzsoft.net/ccproxy/install.htm
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http://www.dell.com/support/article/in/en/indhs1/how10169/configuring-
windows-server-2012-r2-as-a-router?lang=en
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