NETWORKING INTERVIEW QUESTIONS - 1

NETWORKING INTERVIEW QUESTIONS

What is the use of Tracert or Trace Route command?

Tracert (to trace the routes) command used to find the routes. The packets travelling 

from Source to Destination. (How many routers is crossing from source to destination 

we can

Find Maximum of 30 hops. [Include your networks also])

C:\>tracert google.co.in

Tracing route to google.co.in [74.125.236.55]

Over a maximum of 30 hops:

1 1 ms 1 ms <1 ms 150.191.112.161 [your network]

2 21 ms 21 ms 21 ms 121.240.2.54

3 25 ms 25 ms 25 ms 121.240.2.57

4 25 ms 25 ms 25 ms 115.113.165.98

5 20 ms 19 ms 19 ms 209.85.241.52

6 21 ms 21 ms 21 ms 209.85.205.95

7 22 ms 21 ms 24 ms 209.85.211.33

8 21 ms 20 ms 20 ms maa03s04-in-f23.1e100.net

……

[74.125.236.55]

Trace completed.

Tracert command is a Network tool.

Windows workstations are using Tracert command.  Tracert utility is replying on ICMP 

echo requests.

Cisco devices are using trace route command. Trace route is replying with UDP packets 

with a destination port of 33434

What is a ip default Gateway?

The exit point from one network and entry point to another network.

often the router of the network.

Not configured any routing protocol in the router. if IP routing mode disabled.

Non-routing network device that need to connect any network outside device 

Need to have a default-gateway.

#IP defaut-gateway X.X.X.X

x.x.x.x - represents an IP address.

What is default-network?

They are used to route any packets, which don't have any  route information 

match the routing table.  [routing protocol enabled network].

# IP default-network x.x.x.x

x.x.x.x – represents the Network.

How do you set a default route on an IOS Cisco router?

They are used to route any packets (from this router)

#IP route 0.0.0.0 0.0.0.0 x.x.x.x

x.x.x.x – represents the destination address or Exit Interface.

Default route identify by network and subnet mask values are zero (0).

What is three-way handshake in TCP?

This process shortly we tell syn, syn-ack, and ack.

Source and destination device exchanging few control packets before data 

communication process (During the TCP initialization Process) is called Three-way 

Handshake.

What is ARP?

Address Resolution Protocol used to find the MAC (Physical Address) of another Host. 

[From the well-known IP address of the host in the same network].

What is Reverse ARP?

Reverse ARP used to find the Ip address of the host. [From the well-known MAC 

address of the host in the same network].

What is Proxy ARP?

Node configure with default gateway (router) address. The gateway (router) goes 

down. Node will not configure automatically to another default gateway address until 

system admin configure manually. We cannot configure more than one gateway 

address in the node. So if you enable Proxy ARP protocol helps the node to 

automatically connect from this subnet to another remote subnet without configuring. 

(Gateway router goes down).

What is PING command and usage?

Packet Internet Groper, Ping is a utility used to verity the network connectivity of any 

network or any Host.

What is administrative distance?

Administrative Distance starting from 0 to 255. Based on this value trust worthiness of

routing information between routers. The AD is used as the tiebreaker when a router 

has different path form different routing protocol to the same destination. The path 

lowest AD is the priority.

Administrative Distance:

Default route - 0

Static -1

Summary route EIGRP - 15

External BGP - 20

Internal EIGRP - 90

OSPF - 110

IS-IS - 115

RIP  - 120

External EIGRP - 170

Internal BGP - 200

Unknow - 255.

The path lowest AD  is the priority.

What is Matric?

Matric is distance between source and destination... This Matric will different 

from one protocol to another protocol. example RIP matric value 16 hops.

OSPF Metric we called as Cost =bandwidth/10 power 8

EIGRP metric = bandwidth, load, delay, reliability and MTU (default 

consideration Bandwidth and delay  k1 and K3).

What is routing?

Routing is a process moving data from one network to another network based 

on its IP address. (Moving data between sources to destination).

Explain Routing Protocol and routed Protocol?

Routing Protocol:

Routing protocol helps the router to build the routing table automatically, find the best 

path to travel the packets from source to destination based on the routing table and 

exchanging the routing information between the routers.

RIP, EIGRP, IGRP, OSPF, BGP, IS-IS.

Routed Protocols:

Router Protocol helps the router to forward data packets from one router to another 

router.

Shortly routed protocol used to send Data packets to outside network.

IP – Internet Protocol, IPX –Internet packet exchange, SPX – Sequence Packet Exchange

(Novell), Apple Talk.

What are the types of routing & Explain them?

Static Routing

Dynamic Routing

Default static routing

Static Routing: The route information (what are the networks wants to connect)

administrator manually entered router.

Dynamic Routing: The administrator only enters directly connected networks.

routing protocol will automatically update the route information between

routers. Routing Protocol RIP, IGRP, EIGRP, OSPF.

Default Static Routing:

It is used to send packets with a remote destination network not in the routing table to 

the next hop router. We can use default routing only in the stub network.

Stub network - means router having only one exit interface

What is Classful routing and Classless routing?

Classful: routing protocol don’t sends subnet mask information in the routing 

updates.All devices in the network must use the same subnet mask.

Classless Routing: Routing protocol sends subnet mask information in the 

routing updates.Classless routing allows VLSM.

What is Collusion Domain and Broadcast Domain?

Collusion Domain: The packets are collided with one another due to being sent on the 

same shared media. [It is a Logical network segment].

Switches are breakup Collusion domain. Collusion domain can’t be a broadcast domain.

Broadcast Domain: The traffic is transmitted out to all the connected network devices,

Provided that the devices share the same subnet or in the same VLAN. [It is a Logical

Network segment].

Router breakup broadcast domain. Broadcast domain can be a collusion domain.

What is the use of ipconfig command?

IP This utility allows you to get the IP address information of a Windows 

computer. It also allows some control over active TCP/IP connections.

ipconfig Usage:default command contains the IP address, network mask and 

gateway for all physical and virtual network adapter.

Ipconfig /all

This option displays the same IP addressing information for each adapter as the 

default option. Additionally, it displays DNS and WINS settings for each adapter.

ipconfig /release

ipconfig /release "Local Area Connection 1"

ipconfig /release *Local*

ipconfig /renew

How to configure ip address in command prompt?

Netsh command:

netsh interface ip set address name="local area network" static x.x.x.x x.x.x.x x.x.x.x 1

netsh interface ip set address "local area network" dhcp

netsh interface ip set dns "local area connection" static x.x.x.x

netsh interface ip set dns "local area connection" dhcp

How many host can configure in 192.168.1.24 /28?

Network Address: 192.168.1.24

Subnet mask: 255.255.255.240 = 28 

11111111.11111111.11111111.1111 0000

Network: 192.168.1.16/28 (Class C)

Broadcast: 192.168.1.31

First Host : 192.168.1.17

Last Host : 192.168.1.30

Hosts/Net: 14

What is DHCP & Advantages of DHCP?

DHCP – Dynamic Host Configuration Protocol helps the Host to obtaining the IP Address

setting from DHCP Server automatically.

Settings include - IP address, subnet mask, default gateway & DNS.

Advantages if you want to change the DNS server address only change in the

DHCP Server, next time login to client it will update automatically.

What is the Process that a client obtains an IP address from DCHP Server?

Process that a client Obtain IP address from DHCP Server

Discover

Request

Offer

Acknowledge

What is the Port number of DNS, DHCP, Telnet, Http, Https, FTP, SSH, 

SMTP, POP3 & RDP... etc?

DNS – 53

DHCP – 67

Telnet – 23

Http – 80

Https – 443

FTP – 20,21

SSH – 22

SMTP – 25

NNTP – 119

SNMP - 160

POP3 – 110

RDP -3389

Secure SMTP – 465

Secure POP3 - 995

What is DHCP snooping? 

DHCP snooping is a layer 2 security technology built into the operating 

system of a capable network switch that drops DHCP traffic determined to be 

unacceptable. The fundamental use case for DHCP snooping is to prevent 

unauthorized (rogue) DHCP servers offering IP addresses to DHCP clients

What is Hub and Spoke?

In a hub & spoke design, there is a network core router or routers. That is the 

hub. There are multiple remote or local LANs that connect to the core routers 

via LAN or WAN links. These are called spokes. The "Hub & Spoke"