What is a port?
A port is a virtual point where network connections
start and end. Ports are software-based and managed by a computer's operating
system. Each port is associated with a specific process or service. Ports allow
computers to easily differentiate between different kinds of traffic: emails go
to a different port than webpages, for instance, even though both reach a
computer over the same Internet connection.
একটি পোর্ট হল একটি ভার্চুয়াল পয়েন্ট যেখানে নেটওয়ার্ক সংযোগ শুরু এবং শেষ হয়। পোর্টগুলি সফ্টওয়্যার-ভিত্তিক এবং একটি কম্পিউটারের অপারেটিং সিস্টেম দ্বারা পরিচালিত হয়। প্রতিটি পোর্ট একটি নির্দিষ্ট প্রক্রিয়া বা
পরিষেবার সাথে যুক্ত। পোর্টগুলি কম্পিউটারগুলিকে বিভিন্ন ধরণের ট্র্যাফিকের মধ্যে সহজেই পার্থক্য করতে
দেয়: ইমেলগুলি ওয়েবপৃষ্ঠাগুলির চেয়ে আলাদা পোর্টে যায়, উদাহরণস্বরূপ, যদিও উভয়ই একই ইন্টারনেট সংযোগের
মাধ্যমে একটি কম্পিউটারে পৌঁছায়।
What is a port
number?
Ports are standardized across all network-connected
devices, with each port assigned a number. Most ports are reserved for
certain protocols — for example, all Hypertext Transfer Protocol (HTTP) messages go to port 80. While IP addresses enable messages to go to and from specific
devices, port numbers allow targeting of specific services or applications
within those devices.
পোর্টগুলি সমস্ত নেটওয়ার্ক-সংযুক্ত ডিভাইস জুড়ে প্রমিত করা হয়, প্রতিটি পোর্টে একটি নম্বর বরাদ্দ করা হয়। বেশিরভাগ পোর্ট নির্দিষ্ট প্রোটোকলের জন্য সংরক্ষিত - উদাহরণস্বরূপ, সমস্ত হাইপারটেক্সট ট্রান্সফার প্রোটোকল (HTTP) বার্তাগুলি 80 পোর্টে যায়৷ IP ঠিকানাগুলি নির্দিষ্ট ডিভাইসগুলিতে এবং থেকে বার্তাগুলিকে যেতে সক্ষম করে, পোর্ট নম্বরগুলি সেই ডিভাইসগুলির মধ্যে নির্দিষ্ট পরিষেবা বা অ্যাপ্লিকেশনগুলিকে লক্ষ্য করার অনুমতি দেয়৷
How do ports
make network connections more efficient?
Vastly different types of data flow to and from
a computer over the same network connection. The use of ports helps
computers understand what to do with the data they receive.
Suppose Bob transfers an MP3 audio recording to
Alice using the File Transfer Protocol (FTP). If Alice's computer passed the
MP3 file data to Alice's email application, the email application would not
know how to interpret it. But because Bob's file transfer uses the port
designated for FTP (port 21), Alice's computer is able to receive and store the
file.
Meanwhile, Alice's computer can simultaneously load
HTTP webpages using port 80, even though both the webpage files and the MP3
sound file flow to Alice's computer over the same WiFi connection.
একই নেটওয়ার্ক সংযোগের মাধ্যমে একটি কম্পিউটারে এবং থেকে বিভিন্ন ধরণের ডেটা প্রবাহ। পোর্টের ব্যবহার কম্পিউটারগুলিকে বুঝতে সাহায্য করে যে তারা প্রাপ্ত ডেটার সাথে কী করবে৷
ধরুন বব ফাইল ট্রান্সফার প্রোটোকল (FTP) ব্যবহার করে একটি MP3 অডিও রেকর্ডিং অ্যালিসে স্থানান্তর করে। যদি অ্যালিসের কম্পিউটার MP3 ফাইলের ডেটা অ্যালিসের ইমেল অ্যাপ্লিকেশনে পাস করে তবে ইমেল অ্যাপ্লিকেশনটি কীভাবে এটি ব্যাখ্যা করতে হবে তা জানবে না। কিন্তু যেহেতু ববের ফাইল ট্রান্সফার এফটিপি (পোর্ট 21) এর জন্য নির্ধারিত পোর্ট ব্যবহার করে, অ্যালিসের কম্পিউটার ফাইলটি গ্রহণ এবং সংরক্ষণ করতে সক্ষম।
এদিকে, অ্যালিসের কম্পিউটার একই সাথে পোর্ট 80 ব্যবহার করে HTTP ওয়েবপেজ লোড করতে পারে, যদিও ওয়েবপেজ ফাইল এবং MP3 সাউন্ড ফাইল উভয়ই একই ওয়াইফাই সংযোগের মাধ্যমে অ্যালিসের কম্পিউটারে প্রবাহিত হয়।
Are ports part of the network layer?
The OSI model is a conceptual model of how the Internet works. It divides
different Internet services and processes into 7 layers. These layers are:
Ports are a
transport layer (layer 4) concept. Only a transport protocol such as the Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) can indicate which port a packet should go
to. TCP and UDP headers have a section for indicating port numbers. Network layer protocols — for instance, the Internet Protocol (IP) — are unaware of what port is in use in a
given network connection. In a standard IP header, there is no place to
indicate which port the data packet should go to. IP headers only indicate the destination IP address,
not the port number at that IP address.
Usually, the
inability to indicate the port at the network layer has no impact on networking
processes, since network layer protocols are almost always used in conjunction
with a transport layer protocol. However, this does impact the functionality of
testing software, which is software that "pings" IP addresses
using Internet Control Message Protocol (ICMP) packets. ICMP is a network layer protocol
that can ping networked devices — but without the ability to ping specific
ports, network administrators cannot test specific services within those
devices.
Some ping software,
such as My Traceroute, offers the option to send UDP packets. UDP is a
transport layer protocol that can specify a particular port, as opposed to
ICMP, which cannot specify a port. By adding a UDP header to ICMP packets,
network administrators can test specific ports within a networked device.
Why do firewalls
sometimes block specific ports?
A firewall is a security system that blocks or allows network traffic based
on a set of security rules. Firewalls usually sit between a trusted network and
an untrusted network; often the untrusted network is the Internet. For example,
office networks often use a firewall to protect their network from online
threats.
Some attackers try to send malicious traffic to
random ports in the hopes that those ports have been left "open,"
meaning they are able to receive traffic. This action is somewhat like a car
thief walking down the street and trying the doors of parked vehicles, hoping
one of them is unlocked. For this reason, firewalls should be configured to
block network traffic directed at most of the available ports. There is no
legitimate reason for the vast majority of the available ports to receive
traffic.
Properly configured firewalls block traffic to all
ports by default except for a few predetermined ports known to be in common
use. For instance, a corporate firewall could only leave open ports 25 (email),
80 (web traffic), 443 (web traffic), and a few others, allowing internal
employees to use these essential services, then block the rest of the 65,000+
ports.
As a more specific example, attackers sometimes
attempt to exploit vulnerabilities in the RDP protocol by sending attack traffic
to port 3389. To stop these attacks, a firewall may block port 3389 by default.
Since this port is only used for remote desktop connections, such a rule has
little impact on day-to-day business operations unless employees need to work
remotely.
একটি ফায়ারওয়াল হল একটি নিরাপত্তা ব্যবস্থা যা নিরাপত্তা নিয়মের একটি সেটের উপর ভিত্তি করে নেটওয়ার্ক ট্র্যাফিককে ব্লক করে বা অনুমতি দেয়। ফায়ারওয়াল সাধারণত একটি বিশ্বস্ত নেটওয়ার্ক এবং একটি অবিশ্বস্ত নেটওয়ার্কের মধ্যে থাকে; প্রায়শই অবিশ্বস্ত নেটওয়ার্ক হল ইন্টারনেট। উদাহরণস্বরূপ, অফিস নেটওয়ার্কগুলি প্রায়ই তাদের নেটওয়ার্ককে অনলাইন হুমকি থেকে রক্ষা করার জন্য একটি ফায়ারওয়াল ব্যবহার করে।
কিছু আক্রমণকারী র্যান্ডম পোর্টে দূষিত ট্র্যাফিক পাঠানোর চেষ্টা করে এই আশায় যে সেই পোর্টগুলিকে "খোলা" রেখে দেওয়া হয়েছে, যার অর্থ তারা ট্রাফিক পেতে সক্ষম। এই ক্রিয়াটি কিছুটা এমন একটি গাড়ি চোর রাস্তায় হাঁটছে এবং পার্ক করা যানবাহনের দরজা চেষ্টা করছে, আশা করছে যে তাদের মধ্যে একটি আনলক করা হয়েছে। এই কারণে, বেশিরভাগ উপলব্ধ পোর্টে নির্দেশিত নেটওয়ার্ক ট্র্যাফিক ব্লক করতে ফায়ারওয়ালগুলি কনফিগার করা উচিত। উপলভ্য পোর্টের বিশাল সংখ্যাগরিষ্ঠ ট্রাফিক পাওয়ার জন্য কোন বৈধ কারণ নেই।
সঠিকভাবে কনফিগার করা ফায়ারওয়ালগুলি সাধারণ ব্যবহারে পরিচিত কয়েকটি পূর্বনির্ধারিত পোর্ট ব্যতীত ডিফল্টরূপে সমস্ত পোর্টে ট্র্যাফিক ব্লক করে। উদাহরণস্বরূপ, একটি কর্পোরেট ফায়ারওয়াল শুধুমাত্র খোলা পোর্ট 25 (ইমেল), 80 (ওয়েব ট্র্যাফিক), 443 (ওয়েব ট্র্যাফিক) এবং আরও কয়েকটি রেখে যেতে পারে, যা অভ্যন্তরীণ কর্মীদের এই প্রয়োজনীয় পরিষেবাগুলি ব্যবহার করার অনুমতি দেয়, তারপর বাকি 65,000+ ব্লক করতে পারে। বন্দর
আরও সুনির্দিষ্ট উদাহরণ হিসেবে, আক্রমণকারীরা কখনও কখনও পোর্ট 3389 এ আক্রমণ ট্র্যাফিক পাঠিয়ে RDP প্রোটোকলের দুর্বলতাগুলিকে কাজে লাগানোর চেষ্টা করে৷ এই আক্রমণগুলি বন্ধ করতে, একটি ফায়ারওয়াল ডিফল্টরূপে পোর্ট 3389 ব্লক করতে পারে৷ যেহেতু এই পোর্টটি শুধুমাত্র দূরবর্তী ডেস্কটপ সংযোগের জন্য ব্যবহার করা হয়, এই ধরনের নিয়ম প্রতিদিনের ব্যবসায়িক ক্রিয়াকলাপের উপর সামান্য প্রভাব ফেলে যদি না কর্মীদের দূর থেকে কাজ করার প্রয়োজন হয়।
What are the
different port numbers?
There are 65,535 possible port numbers, although
not all are in common use. Some of the most commonly used ports, along with
their associated networking protocol, are:
· Ports 20 and 21: File Transfer Protocol (FTP). FTP is for
transferring files between a client and a server.
· Port 22: Secure Shell (SSH). SSH is one of many tunneling protocols that create
secure network connections.
· Port 25: Simple Mail Transfer Protocol (SMTP). SMTP is
used for email.
· Port 53: Domain Name System (DNS). DNS is an essential process for the modern
Internet; it matches human-readable domain names to machine-readable IP addresses, enabling
users to load websites and applications without memorizing a long list of IP
addresses.
· Port 80: Hypertext Transfer Protocol (HTTP). HTTP is
the protocol that makes the World Wide Web possible.
· Port 123: Network Time Protocol (NTP). NTP allows computer clocks to sync with each
other, a process that is essential for encryption.
· Port 179: Border Gateway Protocol (BGP). BGP is essential for establishing efficient
routes between the large networks that make up the Internet (these large
networks are called autonomous systems). Autonomous systems use BGP to broadcast which IP
addresses they control.
· Port 443: HTTP Secure (HTTPS). HTTPS is the secure and encrypted version of
HTTP. All HTTPS web traffic goes to port 443. Network services that use HTTPS
for encryption, such as DNS over HTTPS, also connect at this port.
· Port 500: Internet Security Association and Key
Management Protocol (ISAKMP), which is part of the process of setting up secure IPsec connections.
· Port 3389: Remote Desktop Protocol (RDP). RDP enables users to remotely connect
to their desktop computers from another device.
The Internet Assigned Numbers Authority (IANA)
maintains the full list of port numbers and protocols assigned to them.
1. What is one of the
latest Computer Processors (CPU)?
The Intel Pentium Quad
Core Intel I3, I5, and I7 processors.
2. What does USB stand
for?
Universal Serial Bus – the
current version is 2.0. It allows the connection of peripherals without the
need to shut down the computer.
3. Which desktop operating
systems are you familiar with?
You will need to have
familiarised yourself with the system used by the organisation you are hoping
to join. Focus your answer on those systems, but also mention other systems
with which you have experience.
4. What are the
disadvantages of using imaging software?
This question is designed
to test your familiarity with imaging software. Describe image testing and the
attributes of particular software to show your familiarity with imaging.
5. Define Hard-Disk
Partitions.
Hard disk partitions
divide the hard disk drive into smaller segments to enable better space
management. Each partition on the disk can then be considered as a separate
disk allowing different file systems to be used on each.
6. What is the difference
between RAM and ROM? RAM stands for Random Access Memory.
It is used for the
temporary storage of data that is being worked on. ROM is Read-Only Memory and
is used for permanent storage of data that should never be changed, like BIOS
for example.
7. If the audio for your
computer is not working, what would you check?
Check the following:
·
Speaker
volume
·
Cable
connections
·
Power
to the speakers
·
Device
drivers.
8. What are the lights on
a Modem/LAN Card and what do they indicate?
The lights are:
·
Power
light - indicates if the power is on
·
Link
light - indicates if the modem is receiving broadband or internet signals from
the ISP
·
Data
light - indicates if the internet is working
·
Connectivity
light - indicates if the modem is connected to a computer
9. What are some of the
Ports available on a computer?
Common ports are:
·
PS/2
ports, for keyboard and mouse
·
USB
ports
·
Sound
ports
·
LAN
or Ethernet ports
·
VGA
ports
10. What does DHCP stand
for and what is its purpose?
Dynamic Host Configuration
Protocol – it assigns dynamic IP addresses to network devices allowing them to
have a different IP address each time they are connected to the network.
11. What does DNS stand
for and what is it used for?
Domain Name Service (or
System or Server) – it translates domain names into IPaddresses.
12. List five Microsoft
Office applications.
·
MS
Word
·
MS
Excel
·
MS
PowerPoint
·
MS
Outlook
·
MS
Access
13. What are some versions
of Windows XP?
·
XP
Professional
·
XP
Home
·
Media
Centre
·
Tablet
PC and Mobile
14. What components are
needed to set up a Basic Home Network?
·
Router/Hub
·
LAN
cards
·
LAN
cables
15. What is the purpose of
BOOT.INI?
Boot.ini is used to decide
which operating system options are displayed during the start-up process.
16. Identify a few
Firewalls.
There are two basic types
of firewall – network layer, which makes decisions based on source and
destination addresses, and application layer, which are hosts run on proxy
servers and allow no direct traffic between networks. Comodo
and Zone Alarm are two commonly used firewalls.
1. How do you feel about
your abilities as a manager?
Focus on how you achieve
results while maintaining good staff relations. Use examples of your
successes and how you have learned from mistakes. Emphasise your energy and
experience.
2. What is your style of
management?
Tailor your answer to the
management style of the company to show that your style will complement it. A
good maxim to remember is ‘task needs, group needs and individual needs’. You
might also mention motivation and delegation.
3. What qualities do you
look for when you hire people?
Mention ability and
experience and interpersonal skills. You should also mention initiative and
future potential.
4. In our industry, what
are some important trends that you see?
This question is intended
to test your knowledge of the industry. You will need to have done some
homework. You might look at topics like technological developments, economic
challenges and changes in the market.
5. What are your reasons
for leaving your previous/present job?
Be honest and brief but
avoid answers suggesting personality conflicts or that you were dismissed. Try
to present the move in a positive light.
6. Have you ever had to
fire someone? If so, why did you have to do so, and how did you approach the
situation? Mention that the task was not pleasant but that you got through by
explaining the position and reasons for dismissal to the individual and being
as sympathetic as possible.
7. Your resume shows that
you may be over-qualified for this position. What is your opinion of this?
You hope to work long term
with the company and hope that good work performance will open up new
opportunities within it. You can mention that strong companies always need
well-qualified staff and that with your qualifications the employer will see a
good and rapid return on his investment.
8. What, in your opinion,
is the most difficult aspect of being a manager or executive?
Identify one of the most
difficult tasks as being the motivation of staff in trying circumstances.You
can include planning and completing objectives on time and within budget.
9. What do you feel is an
appropriate salary for this position?
Salary is a delicate
question. You can answer in several ways. You can give a figure based on
industry norms for the position or else you could say that you cannot give a
realistic answer until you know more details of the job. Do not undersell
yourself - you will regret giving a figure that is too low. Equally, if the
figure is too high, you will put off the employer. It is best to avoid being
too specific but do not give the impression that salary is unimportant.
10. How do you remain
abreast of new developments in technology?
You could mention
seminars, courses, trade journals and technology magazines. You could also
mention the value of social networking.
11. Describe yourself
professionally in a few words.
This is not an invitation
to give your life story. Give a brief mention of your highest education level,
say where you have worked and your role focusing on your most recent position
and then refer to your future goals. You should devote no more than one
sentence to each aspect.
12. If your previous
manager was in the room with us, what do you think he would have to say about
you?
Always try to be positive.
Give answers like: “ They would say that I was an
enthusiastic, hard worker” or “ I was the most reliable and efficient member of
the team’ or “I was an excellent problem solver.”
13. What are some
questions you would ask to help isolate a user’s problem?
This question examines
your problem-solving ability. You could say that you would ask the following
questions:
·
Describe
the problem. Was there an error message? If so, what?
·
Have
you had a similar problem or other problems before? Give details.
·
What
were you doing when the system failed?
·
Has
any new hardware been added to the system?
·
Has
any new software been added to the system?
·
Have
you downloaded anything from the Internet?
·
What,
if anything, have you done to fix the problem yourself?
·
Are
you the only user who has access to the system?
14. What is your favourite
aspect of desktop support?
The question is a test of
motivation. You need to match your answer to the job. Mention aspects like the
challenges of working with new systems and meeting new people.
15. How capable do you
think you are at handling stress?
Here you need to
acknowledge that sometimes work and life can be stressful. You need to show
what techniques you use to reduce and control stress – careful time management,
exercise, time out, setting priorities are all methods you could discuss.
1. A customer complains
that his computer is working slowly. What things should you check?
Check the following:
·
Is
start-up time longer than usual?
·
Is
it slower with one particular application or slower overall?
·
Are
there any viruses, malware or spyware?
·
Available
Hard Disk space.
2. What is your
troubleshooting process?
The basic troubleshooting
process is:
·
Identify
the problem
·
Consider
likely causes Test theories to localise the cause
·
Formulate
and implement a plan to solve the problem
·
Verify
that the problem is solved and take steps to prevent it happening again
·
Record
your findings, what action you took and the outcome
3. What is your least
favourite aspect of desktop support?
This is designed to see
how well you will fit with the present team. A
good answer would be along the lines of being unable to solve a problem due to factors outside you control, like
hardware failure for instance.
4. Describe a situation
where you have had to deal with a difficult person and how you handled it? Do
you think you should have done anything differently?
This question is best
answered by reference to a successful outcome to a difficult situation that you
have encountered. In general terms, you could say that you understand the
frustration of end users and that good communication often goes a long way to
resolving issues.
5. Would you describe
yourself as a problem solver? If so, why? Can you give any example
You should obviously give
a positive answer. You should give examples that show that you can think
critically and highlight your skills.
1. What do you know about
our company and our products?
To answer this question,
you must have done your homework and to show it. You will need to know what the
company does and something about its products. You will also need to be aware
of recent developments and know a little about the leading figures in the
company.
2. Why do you want to work
for this organisation?
Let the interviewers know
that you have done some homework by saying that in your job search their
company stood out from the rest because “….”
You should also mention the company’s history, products, philosophy, reputation
etc.
3. What are your reasons
for wanting to work with us?
From your research on the
company, you should be able to spell out what has attracted you to apply for
the position – perhaps they focus on an area of research that you enjoy or
would like to become involved with; maybe they offer opportunities that
competitors do not; or possibly they are active in a field that interests you.
Be careful, though, do not pretend to have an interest in something that you do
not – your deception will be noticed.
1. What are some things
that you look for in a job?
Tailor your answer to the
interviewers’ company. Talk about challenges, job satisfaction, opportunities
and work environment.
2. For what period of time
do you expect to stay with us?
Say that you are looking
for a career in the organisation but will need to remain challenged.
3. What long-term goals do
you have?
Relate to the job
description and the company and describe what progression you would like to see
in that environment.
4. So far, how successful
do you feel have you been?
Here you need to give an
air of quiet confidence. Say that your career progression to date has been
quite good (give examples of how you think you have been successful).
5. Describe three of your
accomplishments over the past few years that you are most proud of.
Identify three of your
best achievements and say why you are most proud of them – you can consider the
difficulties, the outcomes etc.
6. In two or three years
from now, what do you see yourself doing?
This is a test of your ambition and possible loyalty. You should
be clear about what you hope to achieve and could ask the interviewers if your
objectives are a possibility with their company.
1. Tell me about
yourself. This is a go-to icebreaker for
many interviewers, so it’s best to have an answer prepared. Try to think of one
or two things that set you apart from other candidates to include in your
answer, whether those are your technical skills, experiences, or passions.
Example Answer:
“I’ve been a network engineer for
six years, and during that time, I’ve worked for startups,
Fortune 500 companies, and everywhere in between. I love getting to solve
problems and build the network foundation that many organizations don’t think
about but rely on each and every day.”
2. Tell
me about your experience as a network engineer. Before
you get to your interview, prepare for this question by looking over your resume again.
Take note of the highlights and turning points in your career, and bring them
up in your answer.
Make sure you add information that isn’t
on your resume. What did you learn in each position? How do they all link
together to form your current skill set?
Example Answer:
“I graduated from the University of
Pennsylvania in 2010, and I started working at the university as a
network engineer right
after graduation. That position gave me two years of great on-the-job training,
and I was able to get a job at Tristate Banks, where I worked for five years as
a network engineer.”
“During my time there, I was able to
help scale up the company’s systems to meet its needs as it expanded from 200
employees my first year to 1,500 four years later. Since it was a bank, I also
got experience keeping up with the top security measures.”
3. Why did you become a network engineer? Your
interviewers want to get to know you and hear what makes you tick. They also
want to know if you really are passionate about your work or if you’re just
looking to make it through the day and to your paycheck.
Use this question as an opportunity to
share your journey and what you’re passionate about in your work.
Example Answer:
“In college, I couldn’t decide what I
wanted to do. I knew I liked computers, though, so I decided to take an
entry-level class in the network engineering program. I found it fascinating,
and then when I discovered that this field allows you to support companies in
a behind-the-scenes capacity, which I also love, I was sold.”
4. What do you like best about being a
network engineer? This is another question that
allows interviewers to hear what you love about the job and to see what you
would bring to their team.
Example Answer:
“I enjoy almost every aspect of my work,
but I especially enjoy the problem-solving side of it. I get excited about
hunting down root problems and coming up with creative solutions to fix them. I
especially love when I get to work with a team to do so.”
5. What do you like least about being a
network engineer? Your interviewers want to know
what challenges and drains you and how you respond to those things. This gives
them insight into your attitude about the hard parts of your job, and it helps
them determine if this position would be a good fit for you.
Example Answer:
“Even though I generally enjoy my work,
I do find myself getting discouraged when I accomplish something big and no one
outside of the department is able to appreciate it.”
“I know that’s a part of the job,
though, and I remind myself that I don’t understand all of their
accomplishments either. I also work to focus on the satisfaction of a job well
done and celebrating with my colleagues rather than waiting for a pat on the
back from the rest of the organization.”
6. What
is your greatest strength? This is another good opportunity
to share what sets you apart as a candidate for this position. Don’t brag, but
be honest and explain it from the perspective of how you’ll help the company
rather than how you’re better than everyone else.
Example Answer:
“I’m good at teaching people outside of
my department how to troubleshoot for themselves. Whether it’s resetting a
password or uploading a picture to the website, I find that many people are
able to do those types of tasks, they just don’t know how or are afraid to.”
“I make it my goal to empower these coworkers to take on those tasks for themselves when
possible. I love helping them with their requests, but if I can cut down on the
number of small tasks our department is relied on for, our entire organization
will run more smoothly.”
7. What is your
greatest weakness? If you answer this question with
“nothing,” you’ll send up an immediate red flag that may cost you a job offer.
Employers know that no one is perfect,
and they want to see that you’re self-aware enough to know what your weaknesses
are and that you’re working to mitigate them.
Whether your weakness is a soft skill or a
technical skill, always end your answer to this question by describing the
steps you’re taking to improve.
Example Answer:
“I’m an internal processor, and I’ve had
team leaders get frustrated with me in the past because I leave them out of the
loop on where I’m at on projects. I don’t do this intentionally, I just forget
that they might want to know.”
“So, I’ve started asking my leaders how
often they would like updates on a project and then putting reminders in my
calendar to provide those. This practice has helped me get into the habit of
sharing as I go, and I haven’t had a frustrated manager since I
started doing this.”
8. Tell me about a time when you faced a
problem at work. How did you solve it? Companies want to
hire problem-solvers, so show
your interviewers that you aren’t afraid of facing and overcoming challenges.
Tell a story that demonstrates this, and make sure you share the end results of
your efforts.
Example Answer:
“One day at my last job, as I was about
to leave for the day, our power went out unexpectedly. We had a generator for
our main servers, but we were in an unusual heat wave (it was over 100 degrees
outside), so I knew they could quickly overheat in the absence of air
conditioning.”
“I got permission to run to the hardware
store, where I bought a cheap generator and a bunch of fans. I jimmy-rigged air
conditioning systems to keep the servers at least somewhat cool if the power
didn’t come back on for the night. Sure enough, it stayed out until early the
next morning, but the servers hadn’t overheated.”
9. Tell
me about a time you had to work with a difficult coworker.
How did you handle it? You won’t always naturally get
along with everyone you meet in the workplace, so hiring managers want to know
how you’ll respond when this happens.
Example Answer:
“I was assigned to a project with a
colleague who was known for being standoffish and difficult to work with. He
had worked at the company for much longer than I had at that point, so during
our first meeting, I asked how things had changed over the years at the
organization.”
“Since it wasn’t a personal question, I
guess he felt more comfortable talking about it, because we talked for 20
minutes. The project went smoothly, and since then, we’ve gotten along well.”
10.
Tell
me about a mistake you made while working as a network engineer. How did you
respond? Everyone makes
mistakes, so your interviewers want to see how you handle yours. Be
truthful about a mistake you made, and wrap up your story by explaining how you
ensured it wouldn’t happen again.
Example Answer:
“During my first year on the job, I got
too confident and released an update for our website that I hadn’t had anyone
else check yet. It ended up shutting down our whole website, which was a big
deal, since we do most of our business online.”
“As soon as I figured out what had
happened, I told my supervisor,
apologized, and asked for help. Thankfully he was able to resolve it quickly,
and since then I haven’t released anything major without having someone else
look over it first.”
11.
What
are three adjectives your coworkers would use to
describe you? Your interviewers want to see if
you’d fit the organization’s culture well, so they might ask you a question
along these lines.
Example Answer:
“I’ve actually had my coworkers describe me as reliable and efficient. I believe
they’d also describe me as helpful, because I actually enjoy managing the help
desk, which is a task others on my team are eager to give up.”
12.
What
is your greatest accomplishment? What is the bullet
point on your resume that you’re most proud of? Now is the time to share your
success.
Example Answer:
“At my last position, I saw the need for
a single sign on system for the organization. My manager told me that I could
present my idea to our COO and set up the meeting. After I gave my
presentation, the COO said that she liked it and gave me permission to pursue
the project.”
“A month later, I had successfully
implemented the SSO, and I received many compliments on how helpful it was and
how smoothly the process went.”
13.
Where
do you see yourself in five years? Your interviewers
want to know what your goals are so that they have an idea of whether you’re
planning to be there for the long haul or will want to move on soon.
Example Answer:
“I don’t know for sure where I’m going
to be in five years, but I’d love to be leading a team of network engineers at
that point, ideally at this organization.”
14.
Why do you
want to work here? This question is intended to weed
out any applicants who are just looking for a paycheck
and don’t really care about what happens to the organization as a whole.
While there’s nothing wrong with just
needing a job, companies are more likely to hire someone who knows what their
organization is about and wants to help further it.
Prepare for this question by researching
the company and its values, mission, and vision.
Example Answer:
“I love that the overall mission of this
organization is to assist vulnerable women and children around the world, and
I’d be honored to get to put my skills to work furthering
that mission.”
15.
Walk
me through your process for troubleshooting your network configuration. If
you get this position, you’re likely going to have to actually do this quite a
bit, so explain how you’d do it in detail.
This will give your interviewers a
better idea of how you solve problems, what processes you follow, and whether
or not you’re willing to ask for help.
Example Answer:
“I first check the obvious places where
there might be an issue: network connectivity, hardware failure, or high levels
of activity, to name a few. If those are clear, I’d move to my monitoring and
analytics tools to see if I can find what’s causing the issues there."
“If I don’t find anything quickly, I’d
contact others on my team and in the organization who can help to ask for their
input. This way we can get everything up and running as soon as possible.”
16.
What
sizes of networks have you engineered? This is another
question designed to help interviewers get a better handle on your experience
level. As always, try to emphasize what makes you unique.
Example Answer:
“I’ve set up networks for startups with two people in them and for companies of 2,000
people, which has given me some unique perspective on how to design systems for
small organizations so that they can easily expand.”
17.
How
do you make yourself a better network engineer? Companies want
employees who are intentional about improving both their technical skills and
their soft skills. Describe what you do to make sure you’re always learning and
growing.
Example Answer:
“I make it a goal to attend a
professional development class once a month. Last month was a refresher course
in JavaScript, and this month’s is a class on collaboration and communication.
Sometimes these classes are offered by the company I work for, but others I
complete at home in the evenings or on the weekends.”
18.
This
industry is always changing. How do you go about staying on top of those
changes and innovations? It’s entirely too easy to become
obsolete in this industry, so hiring managers want to know they can trust you
to stay up-to-date. When you answer this question, add some more weight to your
response by including details like publication titles and when you read them.
Example Answer:
“I attend a monthly morning coffee
meeting for network engineers to listen to speakers talk about new developments
and ideas, and I set aside time every Friday morning to read several blogs,
including Network World, Cisco Blogs, and Network Computing.”
19.
What
are the OSI reference model layers? Since you work in a
technical field, be ready for technical questions like this one. Employers want
to make sure that you know what you’re doing, so they might ask you to describe
past projects or answer questions that you haven’t had to think about since you
started working.
If
you don’t know an answer, simply say, “I don’t know, but I’ll look it up
and get back to you,” and then make sure you actually do follow up with the
answer.
Example Answer:
“The OSI layers are the physical layer, the data link layer,
the network layer, the transport layer, the session layer, the presentation
layer, and the application layer.”
20.
Tell
me about a time you’ve scaled a network to accommodate an organization’s
growth. As you know, companies rely
heavily on their network systems being able to support growth. Your potential
employer is likely looking for someone who can help them do this smoothly and
effectively, so there’s a good chance you’ll run across a question like this.
If you don’t have any experience in this
area, you can talk about how you’ve set up your designs to allow for expansion
or what you would hypothetically do in this situation.
Example Answer:
“When I first started working for a startup company, they had already grown from five employees
to 15 and tripled their number of website visitors in one year.”
“They were projecting more growth at
that rate, so I created an on-premises network that was bigger than they needed
at that moment in order to accommodate that expansion. I also integrated those
resources with a web services company in order to expand it further.”
21.
Explain
how you’d limit data loss in a network design. This is a question
that many companies care deeply about, so you’d best be ready to answer it.
Example Answer:
“I make it a habit to incorporate
multiple systems for securing company data, and usually that includes a
combination of regular backups, distributed network storage locations, and
disaster recovery systems.”
22.
What
experience have you had working with development teams and other departments? Companies
don’t just want employees who are skilled at their jobs, they also want people
who can successfully collaborate
with other departments and teams.
When you answer this question, highlight
your communication, conflict resolution, and project management skills.
Example Answer:
“I worked closely with our marketing and
development teams for the four years I spent at my last position. We were all
intentional about sharing our individual goals so that the others would best
know how to support them. As a result, our three departments had some of the
best relationships in the company.”
23.
Tell
me about a time you helped out a team member. Your potential
employer wants to know that you’ll be working to further the team, not just
crossing off your own to-do’s. Talk about a time you
jumped in to help out a colleague, even if it was in a quiet, behind-the-scenes
way.
Example Answer:
“During my first job, I had a team
member who was taking care of a sick family member. She was a good worker,
but that added stress and time off of work had caused her to fall behind. I
decided to work ahead on my projects and let her know that I had set aside an
hour of every day to help her with her tasks.”
“She thanked me, and together we were
able to help her get caught up. Our manager even told us how impressed he was
that we had stayed on track.”
24.
Tell
me about a time you were under a lot of pressure. How did you handle it? Your
interviewers ask this question to see how
you respond to stress and high-pressure situations. Share a story about a
time you handled this well.
Example Answer:
“Only a few months after I began my
first full-time job, my boss was
called away due to a family emergency. I was able to talk to him via email, but
other than that I was on my own.”
“We had been working on a major network
update, and I was going to have to launch it by myself. This was a lot of
pressure on a young employee, so I quickly updated my more experienced
colleagues with the situation and asked if they’d be willing to help check my
work as they had time.”
“They agreed, and I then created a
calendar of deadlines for each of the update steps so that I would be able to
keep everything on track. With a little teamwork and a lot of organization, the
update went off without a hitch.”
25.
What
is your ideal work environment? This question is
designed to help your interviewers determine if you’d be a good cultural fit
for the organization. Be honest in your answer, but also make sure you
communicate that you’re flexible.
Example Answer:
“I work well in most environments,
whether I’m in a noisy workspace or a private office, but I do like to have
some kind of access to my colleagues in order to collaborate with them.”
26.
What is your
ideal management style to work under? Since one of the
main purposes of an interview is to see if you’d be a good fit for the
organization’s culture, it’s likely that you’ll need to answer a question like
this.
Be truthful in your answer, but also try
to highlight how you’re willing and able to work with a variety of
personalities.
Example Answer:
“I have worked with and adapted to a
variety of management styles, but I really thrive when I can go to my manager
with updates and questions throughout a project’s progress. I don’t need to
have my hand held, but I like to have that feedback as I move along to make
sure I’m on the right track.”
27.
Why should we hire
you? This is the queen of all interview
questions, the one that summarizes the whole interview and allows you to make
your pitch about how great you are and why you’re different from all the other
candidates they’re interviewing.
As you answer, talk about what you’d
bring to the organization and why you’d be a valuable hire.
Example Answer:
“With my background working for both
very large and very small companies, I’d bring a unique perspective to your
mid-size company that would allow me to help you both operate at your best now
and easily expand in the future.”
LAN network
LAN stands for Local Area Network. It
refers to the connection between computers and other network devices that are
located within a small physical location.
A node refers to a point or joint where
a connection takes place. It can be a computer or device that is part of a
network. Two or more nodes are needed to form a network connection.
Router
Routers can connect two or more network
segments. These are intelligent network devices that store information in its
routing tables, such as paths, hops, and bottlenecks. With this info, they can
determine the best path for data transfer. Routers operate at the OSI Network
Layer.
It refers to a direct connection between
two computers on a network. A point to point connection does not need any other
network devices other than connecting a cable to the NIC cards of both
computers.
Anonymous FTP is a way of granting user
access to files in public servers. Users that are allowed access to data in
these servers do not need to identify themselves, but instead, log in as an
anonymous guest.
A subnet mask is combined with an IP
address to identify two parts: the extended network address and the host
address. Like an IP address, a subnet mask is made up of 32 bits.
A single segment of UTP cable has an
allowable length of 90 to 100 meters. This limitation can be overcome by using
repeaters and switches.
Data encapsulation is the process of
breaking down information into smaller, manageable chunks before it is
transmitted across the network. In this process that the source and destination
addresses are attached to the headers, along with parity checks.
Network Topology refers
to the layout of a computer network. It shows how devices and cables are
physically laid out, as well as how they connect.
VPN means Virtual Private Network, a
technology that allows a secure tunnel to be created across a network such as
the Internet. For example, VPNs allow you to establish a secure dial-up
connection to a remote server.
NAT is 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.
The Network layer is responsible for
data routing, packet switching, and control of network congestion. Routers
operate under this layer.
Network topology dictates what media you
must use to interconnect devices. It also serves as a basis on what materials,
connectors, and terminations that is applicable for the setup.
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.
There are several ways to do this.
Install a reliable and updated anti-virus program on all computers. Make sure
firewalls are setup and configured correctly. User authentication will also
help a lot. All these combined would make a highly secured network.
NIC is short for Network Interface Card.
This is a peripheral card that is attached to a PC in order to connect to a
network. Every NIC has its own MAC address that identifies the PC on the
network.
WAN network
WAN stands for Wide Area Network. It is
an interconnection of computers and devices that are geographically dispersed.
It connects networks that are located in different regions and countries.
The physical layer does the conversion
from data bits to the electrical signal, and vice versa. This is where network
devices and cable types are considered and setup.
There are four layers: 1) The Network
Layer, 2) Internet Layer, 3) Transport Layer, and 4) Application Layer.
TCP/IP Layers
Proxy servers primarily prevent external
users who are identifying the IP addresses of an internal network. Without
knowledge of the correct IP address, even the physical location of the network
cannot be identified. Proxy servers can make a network virtually invisible to
external users.
This layer provides the protocols and
means for two devices on the network to communicate with each other by holding
a session. This includes setting up the session, managing information exchange
during the session, and tear-down process upon termination of the session.
A fault tolerance system ensures
continuous data availability. This is done by eliminating a single point of
failure.
The 10 refers to the data transfer rate.
In this case, it is 10Mbps. The word Base refers to baseband, as opposed to
broadband.
Private IP addresses are assigned for
use on intranets. These addresses are used for internal networks and are not
routable on external public networks. These ensure that no conflicts are
present among internal networks. At the same time, the same range of private IP
addresses is reusable for multiple intranets since they do not “see” each
other.
NOS, or Network Operating System, is
specialized software. The main task of this software is to provide network
connectivity to a computer in order to communicate with other computers and
connected devices.
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 done by a group of perpetrators. One common method of
doing this is to overload the system server so it cannot anymore process
legitimate traffic and will be forced to reset.
OSI (Open Systems Interconnect) serves
as a reference model for data communication. It is made up of 7 layers, with
each layer defining a particular aspect of how network devices connect and
communicate with one another. One layer may deal with the physical media used,
while another layer dictates how data is transmitted across the network.
The primary purpose of this is to
prevent crosstalk. Crosstalk’s are electromagnetic
interferences or noise that can affect data being transmitted across cables.
By using address translation instead of
routing, address sharing provides an inherent security benefit. That’s because
host PCs on the Internet can only see the public IP address of the external
interface on the computer. Instead, it provides address translation and not the
private IP addresses on the internal network.
MAC, or Media Access Control, uniquely
identifies a device on the network. It is also known as a physical address or
an Ethernet address. A MAC address is made up of 6-byte parts.
The TCP/IP Application layer has three
counterparts on the OSI model: 1) Session Layer, 2) Presentation Layer, and 3)
Application Layer.
By looking at the first octet of any
given IP address, you can identify whether it’s Class A, B, or C. If the first
octet begins with a 0 bit, that address is Class A. If it begins with bits 10
then that address is a Class B address. If it begins with 110, then it’s a
Class C network.
OSPF, or Open Shortest Path First, is a
link-state routing protocol that uses routing tables to determine the best
possible path for data exchange.
Firewalls serve to protect an internal
network from external attacks. These external threats can be hackers who want
to steal data or computer viruses that can wipe out data in an instant. It also
prevents other users from external networks from gaining access to the private
network.
Star topology consists of a central hub
that connects to nodes. This is one of the easiest to set up and maintain.
Star Topology
Advantages:
Here are pros/benefits of start
topology:
Disadvantages:
Here are cons/drawbacks of using Star:
Gateways provide connectivity between
two or more network segments. It is usually a computer that runs the gateway
software and provides translation services. This translation is key in allowing
different systems to communicate on the network.
One major disadvantage of star topology
is that once the central Hub or switch gets damaged, the entire network becomes
unusable.
SLIP, or Serial Line Interface Protocol,
is an old protocol developed during the early UNIX days. This is one of the
protocols that are used for remote access.
10.0.0.0 with a
subnet mask of 255.0.0.0172.16.0.0 with subnet mask of 255.240.0.0192.168.0.0
with subnet mask of 255.255.0.0
Tracert is a
Windows utility program that can use to trace the route taken by data from the
router to the destination network. It also shows the number of hops taken
during the entire transmission route.
A network administrator has many
responsibilities that can be summarized into 3 key functions: installation of a
network, a configuration of network settings, and maintenance/troubleshooting
of networks.
Accessing the resources that are shared
by one of the workstations on the network takes a performance hit.
A hybrid network is a network setup that
makes use of both client-server and peer-to-peer architecture.
DHCP is short for Dynamic Host
Configuration Protocol. Its main task is to assign an IP address to devices
across the network automatically. It first checks for the next available
address not yet taken by any device, then assigns this to a network device.
The main task of the ARP or Address
Resolution Protocol is to map a known IP address to a MAC layer address.
TCP/IP is short for
Transmission Control Protocol / Internet Protocol. This is a set of protocol
layers that is designed to make data exchange possible on different types of
computer networks, also known as a heterogeneous network.
Routers have a built-in console that
lets you configure different settings, like security and data logging. You can
assign restrictions to computers, such as what resources it is allowed access
or what particular time of the day, they can browse the Internet. You can even
put restrictions on what websites are not viewable across the entire network.
Use FTP (File Transfer Protocol) for
file transfers between such different servers. This is possible because FTP is
platform-independent.
Default gateways provide means for the
local networks to connect to the external network. The default gateway for
connecting to the external network is usually the address of the external
router port.
Good passwords are made up of not just
letters, but by combining letters and numbers. A password that combines
uppercase and lowercase letters is favorable than one
that uses all upper case or all lower-case letters. Passwords must be not words
that can easily be guessed by hackers, such as dates, names, favorites, etc. Longer passwords are also better than short
ones.
The proper termination for unshielded
twisted pair network cable is 100 ohms.
Netstat is a
command-line utility program. It provides useful information about the current
TCP/IP settings of a connection.
For a Class C network, the number of
usable Network ID bits is 21. The number of possible network IDs is 2 raised to
21 or 2,097,152. The number of host IDs per network ID is 2 raised to 8 minus
2, or 254.
Cables that are too long would result in
signal loss. It means that data transmission and reception would be affected
because the signal degrades over length.
Software related problems can be any or
a combination of the following:
ICMP is an Internet Control Message
Protocol. It provides messaging and communication for protocols within the
TCP/IP stack. This is also the protocol that manages error messages that are
used by network tools such as PING.
Ping is a utility program that allows
you to check connectivity between network devices on the network. You can ping
a device by using its IP address or device name, such as a computer name.
P2P Network
Peer to peer (P2P) are networks that do
not rely on a server. All PCs on this network act as individual workstations.
DNS is the Domain Name System. The main
function of this network service is to provide host names to TCP/IP address
resolution.
One major advantage of fiber optics is that it is less susceptible to electrical
interference. It also supports higher bandwidth, meaning more data can be
transmitted and received. Signal degrading is also very minimal over long
distances.
Here is the major difference between Hub
and switch:
Hub |
Switch |
A hub operates on the physical layer. |
A switch operates on the data link layer. |
Hubs perform frame flooding that can be unicast,
multicast, or broadcast. |
It performs broadcast, then the unicast and
multicast as needed. |
Just a singular domain of collision is present in a
hub. |
Varied ports have separate collision domains. |
The transmission mode is Half-duplex |
The transmission mode is Full duplex |
Hubs operate as a Layer 1 device per the OSI model. |
Network switches help you to operate at Layer 2 of
the OSI model. |
To connect a network of personal computers should be
joined through a central hub. |
Allow connecting multiple devices and ports. |
Uses electrical signal orbits |
Uses frame & packet |
Does not offer Spanning-Tree |
Multiple Spanning-Tree is possible |
Collisions occur mostly in setups using hubs. |
No collisions occur in a full-duplex switch. |
Hub is a passive device |
A switch is an active device |
A network hub can’t store MAC addresses. |
Switches use CAM (Content Accessible Memory) that
can be accessed by ASIC (Application Specific Integrated Chips). |
Not an intelligent device |
Intelligent device |
Its speed is up to 10 Mbps |
10/100 Mbps, 1 Gbps, 10 Gbps |
Does not use software |
Has software for administration |
There are three main network protocols
supported: NetBEUI, TCP/IP, and IPX.
For Class A, there are 126 possible
networks and 16,777,214 hosts. For Class B, there are 16,384 possible networks
and 65,534 hosts. For Class C, there are 2,097,152 possible networks and 254
hosts
Orange/white, orange, green/white, blue,
blue/white, green, brown/white, brown.
The following are the protocols under
the TCP/IP Application layer: FTP, TFTP, Telnet, and SMTP.
Yes, you can connect two computers,
using only one cable. A crossover type cable can be used in this scenario. In
this setup, the data transmit pin of one cable is connected to the data receive
pin of the other cable, and vice versa.
Ipconfig is a utility program that is
commonly used to identify the addresses information of a computer on a network.
It can show the physical address as well as the IP address.
A straight-through cable is used to
connect computers to a switch, hub, or router. A crossover cable is used to
connect two similar devices, such as a PC to PC or Hub, to the Hub.
Client/server is a type of network
wherein one or more computers act as servers. Servers provide a centralized
repository of resources such as printers and files. Clients refer to a
workstation that accesses the server.
Networking refers to the interconnection
between computers and peripherals for data communication. Networking can be
done using wired cabling or through a wireless link.
Yes, that’s because MAC addresses are
hard-wired into the NIC circuitry, not the PC. This also means that a PC can
have a different MAC address when another one replaced the NIC card.
Clustering support refers to the ability
of a network operating system to connect multiple servers in a fault-tolerant
group. The main purpose of this is the if one server
fails, all processing will continue with the next server in the cluster.
An anti-virus program must be installed
on all servers and workstations to ensure protection. That’s because individual
users can access any workstation and introduce a computer virus. You can plug
in their removable hard drives or flash drives.
.
Ethernet is one of the popular
networking technologies used these days. It was developed during the early
1970s and is based on specifications, as stated in the IEEE. Ethernet is used
in local area networks.
In case one workstation on the network
suffers a malfunction, it can bring down the entire network. Another drawback
is that when there are adjustments and reconfigurations needed to be performed
on a particular network, the entire network must be temporarily brought down.
CSMA/CD, or Collision Detect,
retransmits data frames whenever a collision occurred. CSMA/CA, or Collision
Avoidance, will first broadcast intent to send prior to data transmission.
SMTP is short for Simple Mail Transfer
Protocol. This protocol deals with all internal mail and provides the necessary
mail delivery services on the TCP/IP protocol stack.
Multicast routing is a targeted form of
broadcasting that sends a message to a selected group of the user instead of
sending it to all users on a subnet.
Encryption is the process of translating
information into a code that is unreadable by the user. It is then translated
back or decrypted back to its normal readable format using a secret key or
password. Encryption ensures that information that is intercepted halfway would
remain unreadable because the user must have the correct password or key for
it.
IP addresses are displayed as a series
of four decimal numbers that are separated by period or dots. Another term for
this arrangement is the dotted-decimal format. An example is 192.168.101.2
Authentication is the process of
verifying a user’s credentials before he can log into the network. It is
normally performed using a username and password. This provides a secure means
of limiting access from unwanted intruders on the network.
This is a mode of data exchange wherein
two communicating computers do not use IPsec themselves. Instead, the gateway
that is connecting their LANs to the transit network creates a virtual tunnel.
So, it uses the IPsec protocol to secure all communication that passes through
it.
The mesh topology has a unique network
design in which each computer on the network connects to every other. It is
developing a P2P (point-to-point) connection between all the devices of the
network. It offers a high level of redundancy, so even if one network cable
fails, data still has an alternative path to reach its destination.
Types of Mesh Topology:
Partial Mesh Topology: In this type of topology, most of the
devices are connected almost similarly as full topology. The only difference is
that few devices are connected with just two or three devices.
Partially
Connected Mesh Topology
Full Mesh Topology: In this topology, every node or device
are directly connected with each other.
Fully Connected Mesh Topology
A large percentage of a network is made
up of hardware. Problems in these areas can range from malfunctioning hard
drives, broken NICs, and even hardware startups.
Incorrect hardware configuration is also one of those culprits to look into.
A common way of dealing with such a
problem is to use repeaters and hubs because it will help regenerate the signal
and therefore prevent signal loss. Checking if cables are properly terminated
is also a must.
Instead of having to visit each client
computer to configure a static IP address, the network administrator can apply
dynamic host configuration protocol to create a pool of IP addresses known as
scopes that can be dynamically assigned to clients.
Profiles are the configuration settings
made for each user. A profile may be created that puts a user in a group, for
example.
Sneakernet is believed
to be the earliest form of networking wherein data is physically transported
using removable media, such as disk, tapes.
IEEE, or the Institute of Electrical and
Electronics Engineers, is an organization composed of engineers that issues and
manages standards for electrical and electronic devices. This includes
networking devices, network interfaces, cablings, and connectors.
There are 4 protocols that are being
managed by this layer. These are ICMP, IGMP, IP, and ARP.
Rights refer to the authorized
permission to perform specific actions on the network. Each user on the network
can be assigned individual rights, depending on what must be allowed for that
user.
A VLAN is required because at the switch
level. There is only one broadcast domain. It means whenever a new user is
connected to switch. This information is spread throughout the network. VLAN on
switch helps to create a separate broadcast domain at the switch level. It is
used for security purposes.
IPv6, or Internet Protocol version 6,
was developed to replace IPv4. At present, IPv4 is being used to control
internet traffic but is expected to get saturated in the near future. IPv6 was
designed to overcome this limitation.
RSA is short for the Rivest-Shamir-Adleman algorithm. It is the most commonly used public-key
encryption algorithm in use today.
Mesh topology is a setup wherein each
device is connected directly to every other device on the network.
Consequently, it requires that each device has at least two network
connections.
The maximum allowable length for a
network segment using 100Base-FX is 412 meters. The maximum length for the
entire network is 5 kilometers.
The 5-4-3 rule is used in 10Base2 and
10Base5 Ethernet architectures. In this rule, there can be a maximum of five
segments in a network connected with four repeaters. Out of these five
segments, only three segments can be populated with nodes.
Here are some major differences
between TCP
and UDP protocols:
TCP |
UDP |
It is a connection-oriented protocol. |
It is a connectionless protocol. |
TCP reads data as streams of bytes, and the message
is transmitted to segment boundaries. |
UDP messages contain packets that were sent one by
one. It also checks for integrity at the arrival time. |
TCP messages make their way across the Internet from
one computer to another. |
It is not connection-based, so one program can send
lots of packets to another. |
TCP rearranges data packets in the specific order. |
UDP protocol has no fixed order because all packets
are independent of each other. |
The speed for TCP is slower. |
UDP is faster as error recovery is not attempted. |
Header size is 20 bytes |
The header size is 8 bytes. |
TCP is heavy-weight. TCP needs three packets to set
up a socket connection before any user data can be sent. |
UDP is lightweight. There are no tracking
connections, ordering of messages, etc. |
TCP does error checking and also makes error
recovery. |
UDP performs error checking, but it discards
erroneous packets. |
Acknowledgment segments |
No Acknowledgment segments |
Using handshake protocol like SYN, SYN-ACK, ACK |
No handshake (so connectionless protocol) |
TCP is reliable as it guarantees delivery of data to
the destination router. |
The delivery of data to the destination can’t be
guaranteed in UDP. |
TCP offers extensive error checking mechanisms
because it provides flow control and acknowledgment of data. |
UDP has just a single error checking mechanism that
is used for checksums. |
Here, are three most important elements
of the protocol:
The maximum length for a network segment
using 100Base-FX is 412 meters.
The decoder is a type of circuit that
converts the encoded data to its original format. It also converts the digital
signal into an analog signal.
Brouter is also
known as Bridge Router. It is a device that acts as both a bridge and a router.
As a bridge can forwards data between the networks. It also routes the data to
specified systems within a network.
By using a Virtual Private Network
(VPN), users can connect to the organization’s network. Corporate companies,
educational institutions, government offices.
The OSI model was started in February
1980. In 802.XX, ’80’ stands for the year 1980, and ‘2’ represents the month of
February.
NVT is a set of pre-defined rules to
very simple virtual terminal interaction. This terminal helps you to start a
Telnet session.
The source route is a sequence of IP
addresses that helps you to identify the route a datagram. You can include the
source route in the IP datagram header.
Pipelining describes the sequencing of
processes. When any new task begins before an ongoing task is finished, it is
called sequencing.
The transmission speed of Ethernet is
mostly measured in Mbps.
The length of the Thinnet
cable is 185 meters.
Thicknet cable is
also called as the RG8 cable.
No, Nowadays, coaxial cable no longer
used in a computer network.
Most of the telephone cable uses the
RJ11 connector.
It is a host that has multiple network
interfaces that multiple IP addresses is called a Multi-homed Host.
The full form of EGP is Exterior Gateway
Protocol. It is the protocol of the routers. It is the neighboring
autonomous systems that help you to identify the set of networks that you will
able to reach within or via each independent system.
When a computer in the network listen
and receive the signal, they are called passive topology.
It is a false terminal which allows you
external machines to connect through Telnet or log in. Without this, no
connection can take place.
Redirector is a kind of software which
intercepts file or prints I/O requests and translates them into network
requests. This component comes under the presentation layer.
TCP Three-Way Handshake
THREE-WAY handshake or a TCP 3-way
handshake is a process that is used in a TCP/IP network to make a connection
between the server and client. It is a three-step process that requires both
the client and server to exchange synchronization and acknowledgment packets
before the real data communication process starts.
Hamming
code is a liner code that is useful for error detection up to two
immediate bit errors. It is capable of single-bit errors.
In Hamming code, the source encodes the
message by adding redundant bits in the message. These redundant bits are
mostly inserted and generated at certain positions in the message to accomplish
the error detection and correction process.
Here are some common applications of
using Hemming code:
Here, are important benefits of Hamming
code
MAC address is a unique identifier that
is assigned to a NIC (Network Interface Controller/ Card). It consists of a 48
bit or 64-bit address, which is associated with the network adapter. MAC
address can be in hexadecimal format. The full form of MAC address is Media
Access Control address.
Here are the important reasons for using
MAC address:
Here are the important types of MAC
addresses:
Here, are some difference between MAC
and IP address:
MAC |
IP address |
The MAC address stands for Media Access Control
Address. |
IP address stands for Internet Protocol Address. |
It consists of a 48-bit address. |
It consists of a 32-bit address. |
MAC address works at the link layer of the OSI model. |
IP address works at the network layer of OSI model. |
It is referred to as a physical address. |
It is referred to as a logical address. |
You can retrieve the MAC address of any device using
ARP protocol. |
You can retrieve the MAC address of any device RARP protocol. |
Classes are not used in MAC address. |
In IP, IPv4 uses A, B, C, D, and E classes. |
Analog Signal
Analog signal is a continuous signal in
which one time-varying quantity represents another time-based variable. These
kind of signals works with physical values and natural phenomena such as
earthquake, frequency, volcano, speed of wind, weight, lighting, etc.
Digital Signal
A digital signal is a signal that is
used to represent data as a sequence of separate values at any point in time.
It can only take on one of a fixed number of values. This type of signal
represents a real number within a constant range of values.
Here are the main differences
between Analog and
Digital Signal:
Analog |
Digital |
An analog signal is a
continuous signal that represents physical measurements. |
Digital signals are time separated signals which are
generated using digital modulation. |
It is denoted by sine waves |
It is denoted by square waves. |
It uses a continuous range of values that help you
to represent information. |
The Digital signal uses discrete 0 and 1 to
represent information. |
The analog signal
bandwidth is low |
The digital signal bandwidth is high. |
Analog hardware never offers flexible
implementation. |
Digital hardware offers flexibility in
implementation. |
It is suited for audio and video transmission. |
It is suited for Computing and digital electronics. |
The Analog signal doesn’t offer any fixed range. |
Digital signal has a finite number, i.e., 0 and 1. |
MAN network
A Metropolitan Area Network or MAN is
consisting of a computer network across
an entire city, college campus, or a small region. This type of network is
large than a LAN, which is mostly limited to a single building or site.
Depending upon the type of configuration, this type of network allows you to
cover an area from several miles to tens of miles.
A modem (modulator-demodulator) is a
device that modulates an analog signal to digital
information. It also decodes carrier signals to demodulates the transmitted
information.
The main aim of the Modem is to produce
a signal that can be transmitted easily and decoded to reproduce the digital
data in its original form. Modems are also used for transmitting analog signals, from Light Emitting Diodes (LED) to radio.
Modem
Here, are pros/advantage of Modem:
These interview questions will also help
in your viva(orals)
Q1. What
is a network?
Ans. A network consists of two or more separate devices linked together
such that they can communicate. Networks can be classified according to
different criteria such as scope, type of connection, functional relationship,
topology, or function, among others.
Explore popular courses on Naukri Learning related to
networking:
Q2. What
are the different types of networks?
Ans. Considering the size or span of a network, we can classify them as
follows:
·
PAN (Personal Area Network) –
PAN is made up of devices used by a single person. It has a range of a few
meters.
·
WPAN (Wireless Personal Area Network) –
It is a PAN network that uses wireless technologies as a medium.
·
LAN (Local Area Network) – LAN is a
network whose range is limited to a relatively small area, such as a room, a
building, an aeroplane, etc.
·
WLAN (Wireless Local Area Network) – WLAN is a
LAN network that uses wireless means of communication. It is a widely used
configuration due to its scalability and because it does not require the
installation of cables.
·
CAN (Campus Area Network) – A network of high-speed
devices that connects LANs in a limited geographical area, such as a university
campus, a military base, etc.
·
MAN (Metropolitan Area Network) – MAN is a
high-speed (broadband) network providing coverage in a larger geographic area
than a campus, but still limited.
·
WAN (Wide Area Network) – WAN extends
over a large geographical area using unusual means of communication, such as
satellites, interoceanic cables, fibre optics, etc. Use public media.
·
VLAN – It is a type of logical
or virtual LAN, mounted on a physical network, in order to increase security
and performance. In special cases, thanks to the 802.11Q protocol (also called QinQ), it is possible to mount virtual networks on WAN
networks. It is important not to confuse this implementation with VPN
technology.
For more information, you should
explore: Types Of
Computer Networks
You can also explore – What is the Difference Between LAN and WAN?
Read more – What is Networking?
Q3. What
is Network Cabling?
Ans. Network cables can connect two computers or computer systems directly. A
cable is a cord that is made up of different conductors, which are insulated
from each other. This cord is usually protected by a wrap for better strength
and flexibility.
To choose a network cable, several aspects must be taken into account
such as –
·
The distance that must be covered
with that cable
·
The maximum data transmission
speed
·
The coating of the
cable
·
The type of network to be created
·
The type of braiding, shielding,
and/or sheath
Q4. What
are the different types of network cables used in networking?
Ans. The different types of cables used in networks are –
·
Unshielded Twisted Pair (UTP)
Cable
·
Shielded Twisted Pair (STP) Cable
·
Cable Installation Guides
·
Coaxial Cable
·
Fibre Optic Cable
·
Wireless LANs
Q5. What
is a ‘subnet’?
Ans. A ‘subnet’ is a generic term for a section of an extensive network,
usually separated by a bridge or a router. It also works for the network’s
broadcast domains, manages traffic flow, and helps increasing network
performance. Uses of the subnet in networking include:
·
Relieving network congestion
·
Reallocating IP addresses
·
Improving network security
Q6. What
is DNS?
Ans. The Domain Name System (DNS) is a central part of the internet,
providing a way to match names (a website you’re seeking) to numbers (the
address for the website). Anything connected to the internet – laptops,
tablets, mobile phones, and websites – has an Internet Protocol (IP) address made
up of numbers.
You can also explore: What Is An
IP Address?
Explore – What is network security?
Q7.
Differentiate between ‘forward lookup’ and ‘reverse lookup’ in DNS?
Ans. Following are the major differences between a forward lookup and
reverse lookup in DNS:
Forward DNS lookup |
Reverse DNS lookup |
Converts a human input or a
domain name to an IP address |
Converts an IP address into a
domain name |
Has a mapping between hostnames
and IP addresses |
Has a mapping that relates IP
addresses to hostnames |
Used for a website or other
server access |
Used for network troubleshooting |
Utilizes different servers with
different IP addresses |
Resolves reverse lookup queries
where a client requests a hostname by providing an IP address |
Uses A Records (basic) to
identify any IP address for a particular hostname |
Uses DNS pointer record to
identify a hostname for a given IP address |
Q8.
What is Network Topology?
Ans. This is among the important networking interview questions. Network
topology is the physical or logical arrangement in which the devices or nodes
of a network (e.g. computers, printers, servers, hubs, switches, routers, etc.)
are interconnected with each other over a communication medium. It consists of
two parts – the physical topology, which is the actual arrangement of the
cables (the media), and the logical topology, which defines how the hosts
access the media.
You must explore: What are the Different Types of
Network Topology?
Types of
network topologies –
Bus – In the bus network topology, each workstation is connected to a
main cable called a bus. Therefore, in effect, each workstation is directly
connected to every other workstation on the network.
Bus network topology
Star – In the star network topology, there is a central computer or
server to which all workstations are directly connected. Each workstation is
indirectly connected to the other through the central computer.
Star network topology
Ring – In the ring network topology, the workstations are connected in
a closed-loop configuration. Adjacent workstation pairs are directly connected.
Other pairs of workstations are indirectly connected, passing data through one
or more intermediate nodes.
Mesh – Mesh network topology has two forms – full and partial mesh. In
the full mesh topology, each workstation is directly connected. In the partial
mesh topology, some workstations are connected to all the others, and some are
connected only to the other nodes with which they exchange more data.
Fully Connected Mesh (Left) and
Partial Mesh Network Topology (Right)
Tree – The tree network topology uses two or more star networks
connected to each other. The central computers in star networks are connected
to the main bus. Thus, a tree network is a bus network of star networks.
Tree Network Topology
Q9. What
are ‘client’ and ‘server’ in a network?
Ans. Clients and servers are separate logical entities that work together
over a network to accomplish a task.
A client application is the element of communication that requests or
requests a network service, for example, accessing a web page, or downloading a
file, or sending an email.
A server application is the element of communication that responds to
customer requests, providing the required service, that is, sending the web
page or the requested file or email.
The client-server model is used by computer applications such as email,
the worldwide web, and network printing.
Q10. What
is a ‘frame relay’ and in which layer does it operate?
Ans. Frame Relay is a data link layer digital packet-switched network
protocol technology designed to connect local area networks (LANs) and transfer
data over wide area networks (WANs). Frame Relay shares some of the same
underlying technology as X.25.
It is based on the older X.25 packet-switching technology that was
designed to transmit analogue data as voice conversations. Unlike X.25, which
was designed for analogue signals, Frame Relay is a fast packet technology,
which means that the protocol does not attempt to correct errors. It is often
used to connect LANs with main backbones, as well as in public wide area
networks and in private network environments with leased T-1 lines. It requires
a dedicated connection during the transmission period and is not ideal for
voice or video, which require a constant stream of transmissions.
You can also read: Top Network Security Interview
Questions
Q11. What
are the different features of Frame Relay?
Ans. The different features of Frame Relay are:
·
Frame Relay is a connectionless
service, which means that every data packet that passes over the network
contains address information
·
Frame Relay is a service that is
provided with a variety of speeds from 56 Kbs to 25 Mbs. Although the speeds most used for the service are
currently 56 Kbs and 1,544 Mbs
·
The frames are of variable length
and go up to 4,096 bytes
·
Frame Relay is considered a
broadband ISDN service
·
It operates at high speed (1,544
Mbps to 44,376 Mbps).
·
It operates only on the physical
and data link layers. Therefore, it can be easily used on the Internet.
·
It has a large frame size of 9000
bytes. Therefore, it can accommodate all local area network frame sizes.
·
Frame Relay can only detect
errors (at the data link layer). But there is no flow control or error control.
It operates in the data link layer.
Q12. How
does a Frame Relay Work?
Ans. Frame Relay supports the multiplexing of traffic from multiple
connections over a shared physical link. It uses hardware components that
include router frames, bridges, and switches to pack data into individual frame
relay messages. Each connection uses a 10-bit Data Link Connection Identifier
(DLCI) for unique channel addressing. There are two types of connections:
·
Permanent Virtual Circuits (PVCs)
for persistent connections are intended to be maintained for long periods even
if data is not actively transferred.
·
Switched Virtual Circuits (SVCs)
for temporary connections that last only one session.
Frame Relay then places the data in a variable-size unit called a frame
and leaves any necessary error correction (data retransmission) until the
endpoints, speeding up the overall transmission of data.
Frame Relay
Q13. What
is a MAC address?
Ans. A MAC (Media
Access Control) address is the unique 48-bit hardware address of a LAN card,
usually stored in the ROM of the network adapter card.
The MAC address is a unique identifier that manufacturers assign to a
network card or device. It is also known as a physical address represented by
hexadecimal digits. Each MAC address is unique worldwide and, in theory, they
are fixed for each device.
Each MAC address includes six pairs of numbers. The first three pairs
help to identify the manufacturer and the next three to the specific model. It
is important to bear in mind that a computer may have a variety of hardware to
connect to networks; thus, it is common to have a MAC address for Ethernet, one
for Wi-Fi, and another for Bluetooth.
Q14. What
is ‘beaconing’?
Ans. Beaconing is the process that allows a network to self-repair
network problems. This is among the important networking interview questions
and you must prepare for the related terminologies as well.
Q15.
Differentiate between ‘attenuation’, ‘distortion’, and ‘noise’.
Ans. When a signal travels through a medium, it loses some of its
energy due to the resistance of the medium. This loss of energy is called
attenuation.
When a signal travels through a medium from one point to another, it may
change the form or shape of the signal. This is known as distortion.
Noise is unwanted electrical or electromagnetic energy that degrades the
quality of signals and data.
Q16. What
is an IP address?
Ans. An Internet Protocol address (IP address) is a numerical unique address
of a device in a network. IP is a datagram-oriented connectionless protocol,
therefore each packet must contain a header with the source IP address, the
destination IP address, and other data in order to be delivered successfully.
There are two types of IPs –
·
Private IP Address – A private IP address is a
set of numbers that are assigned to each computer or system, connected to a
private network. An example of a private IP address is your mobile phone or
your home router which have a default local address.
·
Public IP Address – Public IP addresses are
global addresses, visible to anyone browsing the Internet. A user just needs an
internet connection to connect to such devices.
Q17. How
to find the IP address of a website?
Ans. Finding the IP address of a website or a domain is not a tricky
task and involves the below steps –
·
Press the “Start” button on your
computer
·
Type in the program and file
browser “cdm”
·
Hit “Enter”
·
The MS-DOS console will open,
where you must type “nslookup google.com”. Instead of
“google.com”, you must write the domain name of the page you want to consult
·
Next, you will be able to see the
IP address
Q18. What
is ‘bandwidth’?
Ans. The limited range of frequencies of signals that a line can carry
is called the bandwidth. Bandwidth is often confused with Internet speed when
it is actually the volume of information that can be sent over a connection in
a measured amount of time, calculated in megabits per second (Mbps).
Logically the bandwidth of our network will be decisive for its quality
and speed. The more bandwidth we have, the better, since the faster we can
transfer data.
Q19. What
are ‘firewalls’?
Ans. A firewall is a network security system, responsible to manage
network traffic. It uses a set of security rules to prevent remote access and
content filtering. Firewalls are used to protect the systems or networks from
viruses, worms, malware, etc. Firewalls are usually of two types –
Physical – A physical firewall or hardware firewall is a physical device,
sits between the external network and the server. They analyze
incoming traffic and filter out any threats to the device. Widely used in
institutions and large companies.
Logical – A logical or software firewall can exist anywhere on the subnet
and protects hosts anywhere on the subnet without rewiring. They only protect
the computer on which they are installed, and in many cases, they are
integrated into the operating system itself.
You can also explore: What are the Different Types of
Firewalls?
Q20. How
does a firewall work?
Ans. This is among the popularly asked networking interview questions.
The firewall ‘listens’ for what information packets are trying to leave or
enter the computer system. Blocking can be done based on various criteria, such
as the IP to which they are destined, the type of port used to send them, or
the application of origin.
One of the most complex aspects of using firewalls lies in their
configuration, in deciding what types of connections are blocked and which ones
are not.
Q21. What
are the major types of networks?
Ans. There are two major type of networks: Server-based network and
Peer-to-peer network.
Q22. What
are the important topologies for networks?
Ans. There are three essential topologies: Star, Bus, and Ring.
Q23.
Differentiate between static IP addressing and dynamic IP addressing.
Ans. In a static IP address, a computer (or another device) is always
configured to use the same IP address, whereas, in a dynamic IP address, the IP
address can change periodically and is managed by a centralized network
service.
Q24.
What are the different ways to exchange data?
Ans. Following are the different ways to exchange data:
·
Simplex
·
Half-duplex
·
Full-duplex
Q25. What
are routers?
Ans. Routers connect two or more network segments. These intelligent
network devices store information in their routing tables such as paths, hops,
and bottlenecks. They determine the most accurate data transfer paths and
operate in Open Systems Interconnection (OSI) Network Layer.
The roles of a router include:
·
Inter-network communication
·
Best path selection
·
Packet forwarding
·
Packet filtering
For more information, you can
also explore: What is Router in Computer Networks?
You can also explore: Network Devices in Computer
Networks and Its Types
Q26. What
are the criteria for the best path selection of a router?
Ans. The following parameters define the path selection:
·
Longest prefix match
·
Minimum AD (administrative
distance)
·
Lowest metric value
Q27.
Explain what is a source route?
Ans. The source route is defined as a sequence of IP addresses that are used
to identify the route of a datagram. You can also involve the source route in
the IP datagram header.
Q28. What
is the difference between ‘standard’ and ‘extended’ ACL (access control list)?
Ans. Standard ACLs are source-based, whereas extended ACLs are source-
and destination-based.
Q29. What
is data encapsulation?
Ans. Data encapsulation is the process of breaking down information
into smaller, manageable chunks before their transmission across the network.
Q30. What
is RAS?
Ans. RAS (Remote Access Services) refers to any combination of hardware
and software to enable remote access to tools or information that typically
reside on a network of IT devices.
Q31.
Mention the different network protocols that are supported by Windows RRAS
services?
Ans. Following are the three main network protocols supported by
Windows RRAS services:
·
NetBEUI
·
TCP/IP
·
IPX
Q32. What
are the perquisites to configure a server?
Ans. Perquisites to configure a server are:
·
LAN card should be connected
·
Root (partition on which window
is installed) should be in NTFS format.
·
A server should be configured
with a static IP address.
Q33. How
can you secure a computer network?
Ans. You can achieve a secure computer network in the following ways:
·
Install a reliable and updated
antivirus program across the network
·
Ensure firewalls are setup and
configured properly
·
Monitor firewall performance
·
Ensure User authentication
·
Update passwords regularly, every
quarter
·
Create a virtual private network
(VPN)
You can also explore: What is a Virtual Private
Network (VPN)?
Q34.
Mention the uses of the Hamming code?
Ans. Following are some of the common applications of using Hemming
code:
·
Modems
·
Satellites
·
PlasmaCAM
·
Shielding wire
·
Embedded Processor
·
Computer Memory
·
Open connectors
Q35. What
are proxy servers and how do they protect computer networks?
Ans. Proxy servers prevent external users from identifying the IP
addresses of an internal network. They make a network virtually invisible to
external users, who cannot identify the physical location of a network without
knowledge of the correct IP address.
Q36. What
are Nodes and Links?
Ans. Nodes – Devices or data points on a more extensive network are
known as nodes. They are individual parts of a larger data structure and
contain data. They also link other nodes.
Links- A link is the physical and logical network component for
interconnecting hosts or nodes in a network. It is a physical communication
medium such as a coaxial cable or optical fibre.
Q37. What
is SLIP?
Ans. SLIP or Serial Line Interface Protocol was developed during the
early UNIX days and it is used for remote access.
SLIP does not provide error detection as it relies on higher-layer
protocols for it. Therefore, SLIP alone is not successful on an error-prone
dial-up connection. However, it is still useful to test the operating system’s
response capabilities under load (looking at ping flood statistics).
Interviewers often ask such networking interview questions and you must
prepare for such abbreviations.
Q38. What
is TCP/IP?
Ans. TCP/IP is the short form of the Transmission Control Protocol /
Internet Protocol. It is a set of protocol layers designed to facilitate data
exchange on heterogeneous networks.
Learn all about Cisco Certifications, their Scope,
and Benefits, read our blog – what are Cisco Certifications?
Q39. How
many layers does TCP/IP Model have?
Ans. TCP/IP Model has four layers:
Layer |
Description |
Network Interface |
Network Interface is also
called a network access layer. It defines how data should be sent physically
using the network. |
Internet |
It enables hosts to insert
packets into the network and have them delivered to the destination, on the
same network, or another remote network. |
Transport |
This layer permits devices on
the source and destination hosts to carry on a conversation. It ensures
reliability, flow control, and correction of data that is being sent over the
network. |
Application |
It is the topmost layer of the
TCP/IP model. It defines TCP/IP application protocols and how host programs
interface with transport layer services to use the network. |
Q40.
Explain the different layers in the OSI model?
Ans. It is one of the most commonly asked networking interview
questions. The OSI (Open Systems
Interconnection) Model consists of seven layers:
Layer |
Description |
Physical |
It is the lowest layer of the
OSI Model. It transmits raw unstructured data bits over a communication
channel. The Physical layer is responsible for the actual physical connection
between the devices. While receiving data, the Physical layer gets the signal
received, converts it into 0s and 1s, and sends them to the Data Link layer. |
Data Link |
At this layer, the directly
connected nodes perform node-to-node data transfer where data is packaged
into frames. This layer also corrects errors that occurred at the Physical
layer. Data Link Layer is divided into two sub-layers : ·
Logical Link Control (LLC) ·
Media Access Control (MAC) |
Network |
The Network layer is
responsible for transmitting data from one host to the other located in
different networks. It receives frames from the data link layer and delivers
them to their intended destinations based on the addresses contained inside
the frame. It also takes care of packet routing. |
Transport |
The transport layer is
responsible for managing the delivery and error-checking of data packets. It
ensures the end-to-end delivery of the complete message. |
Session |
This layer creates
communication channels, called sessions, between devices. It opens sessions,
ensures they remain open while data is being transferred, and closes them
when communication ends. It is also responsible for authentication and
reconnections. |
Presentation |
This layer extracts data from
the application layer and manipulates it as per the required format to
transmit over the network. |
Application |
At the Application layer, both
the end-user and the application layer interact directly with the software
application. This layer acts as a window for the application services to
access the network and for displaying the received information to the user. |
Q41. A
gateway works in which layer of the OSI model?
Ans. Transport layer.
Q42.
Explain why the standard OSI model is known as 802.xx?
Ans. The OSI model was introduced in February 1980. In 802.XX, ‘80’ is
named for the year 1980, and ‘2’ is named for the month of February.
Q43. What
common software problems lead to network defects?
Ans. It can be any or a combination of:
·
Application conflicts
·
Client-server problems
·
Configuration error
·
Protocol mismatch
·
Security issues
·
User policy & rights issues
This question is among the basic networking interview questions and you
must prepare for such questions.
Q44. Why
is encryption on a network necessary?
Ans. Encryption is the process of changing data from its original
readable format to an unreadable format, thus ensuring network security. It
requires the user to use a secret key or password to decrypt the data.
Encryption is not only useful for communications, but also in any case
where you want to protect sensitive information. Thus, it is possible to
encrypt the information contained in disks, folders or even individual files,
to prevent unauthorized access. Then, in addition to the benefit of protecting
the privacy of users, data encryption prevents other types of attacks such as
identity theft, or bank fraud, in addition to providing a protection mechanism
against the theft or loss of devices with sensitive information.
Q45. What
are the types of errors?
Ans. There are two categories of errors –
·
Single-bit error – one-bit error
per data unit
·
Burst error – Two or more bits
errors per data unit
Q46. What
is a client-server model?
Ans. The client-server model or architecture is a communication
framework for network processes. This framework is distributed among service
requestors, clients, and service providers and offers them transparent access
to applications, data, computing services or any other resource of the
workgroup and/or across the organization, on multiple platforms.
Client-Server Functions
·
User interface management
·
Management of shared peripherals
·
Capture and validation of input
data
·
Generation of queries and reports
on databases
·
Control of concurrent access to
shared databases
·
Create communications links with
other local or wide area networks
Q47. What
is TELNET?
Ans. TELNET is a client-service protocol on the internet or local area
network, allowing a user to log on to a remote device and have access to it.
This is among the most commonly asked networking interview questions.
Technically, it is a bidirectional interactive text-oriented communication
facility, which uses a virtual terminal connection.
Q48. What
is RIP?
Ans. In networking, RIP is an abbreviation for Routing Information
Protocol. It is a simple protocol that exchanges information between the
routers.
Q49. What
is half-duplex?
Ans. It is the mode of communication between two devices. Here the data
flows bi-directionally but simultaneously. A perfect example of a half-duplex
is a walkie-talkie.
Q50. What
is a full-duplex?
Ans. It is a mode of communication between two devices and the data
flow is bi-directional too, but the flow is simultaneous. One of the examples
of full-duplex is a telephone.
Q51. What
is netstat?
Ans. Netstat is a command-line utility
program that provides information about the current Transmission Control
Protocol /Internet Protocol (TCP/IP) settings of a connection.
Q52. What
is a peer-peer process?
Ans. The processes on each machine that communicate at a given layer
are called the peer-peer process.
Q53. What
is anonymous FTP?
Ans. With the help of an anonymous FTP, users can be granted access to
files in public servers. Users can log in as anonymous guests, thus the name.
Q54. What
is NAT?
Ans. It stands for Network Address Translation and is a protocol that
allows a network device, usually a firewall, to assign a public address to a
computer/s inside a private network.
Q55.
Mention a few examples of private network addresses.
Ans. Few examples of private network addresses
are:
10.0.0.0 with a subnet cover of
255.0.0.0172.16.0.0 with subnet cover of 255.240.0.0192.168.0.0 with
subnet cover of 255.255.0.0.
Q56. Can
you tell me the main elements of a protocol?
Ans. There are three main elements of a protocol –
·
Syntax: It refers to the structure or
format of the data and their order of presentation.
·
Semantics: It specifies the meaning of
each section of bits.
·
Timing: Timing refers to two
characteristics, which include the timing of data sending and the speed of data
sending.
Such common networking interview questions are often asked by the
interviewers.
Q57. What
is NIC?
Ans. NIC is the abbreviation for Network Interface Card. It is a
peripheral card with electronic circuitry. It is attached to a PC and connects
to a network. NIC has its own MAC address and this identifies a PC on the
network.
Q58. What
is the difference between Communication and Transmission?
Ans. Transmission –
A process of sending and receiving data between source and destination, in only
one way. It is regarded as the physical movement of data.
Communication – A process of sending and receiving data between source and
destination, in both ways.
Q59.
Explain NAT in networking.
Ans. Network Address Translation (NAT) is a protocol used to convert the IP
address of the computer network into a local network to a single IP address. It
takes all your local network devices and provides a single IP address to share
a single connection to the internet. NAT is used router, computer, firewall in a local network.
Q60.
Explain NOS.
Ans. Short form for Network Operating System. Specialized software that
provides connectivity to a computer such that it can communicate with other
computers and devices on a network.
Q61. What
is IDEA?
Ans. IDEA is the abbreviation for International Data Encryption Algorithm.
It is the replacement for the Data Encryption Standard (DES).
Q62. What
is ASCII?
Ans. American Standard Code for Information Interchange.
Q63. What is Brouter?