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.

Technical IT support interview questions.

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.

Personality based IT support interview questions.

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.

Scenario based interview questions and answers.

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.

Company based IT support job interview questions.

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.

Career IT & desktop support interview questions.

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.

 

 

27 COMMON NETWORK ENGINEER INTERVIEW QUESTIONS AND ANSWERS

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.”

 

4) What is a LAN?

LAN networkLAN 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.

5) What is a node?

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.

6) What are routers?

RouterRouter

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.

7) What is a point to point link?

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.

8) What is anonymous FTP?

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.

9) What is a subnet mask?

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.

10) What is the maximum length allowed for a UTP cable?

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.

11) What is data encapsulation?

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.

12) Describe Network Topology

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.

13) What is a VPN?

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.

14) Briefly describe NAT

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.

15) What is the job of the Network Layer under the OSI reference model?

The Network layer is responsible for data routing, packet switching, and control of network congestion. Routers operate under this layer.

16) How does a network topology affect your decision to set a network?

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.

17) What is RIP?

RIP, short for Routing Information Protocol is used by routers to send data from one network to another. It efficiently manages routing data by broadcasting its routing table to all other routers within the network. It determines the network distance in units of hops.

18) What are the different ways of securing a computer network?

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.

19) What is NIC?

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.

20) What is WAN?

WAN networkWAN 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.

21) What is the importance of the OSI Physical Layer?

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.

22) How many layers are there under TCP/IP?

There are four layers: 1) The Network Layer, 2) Internet Layer, 3) Transport Layer, and 4) Application Layer.

TCP/IP LayersTCP/IP Layers

23) What are proxy servers, and how do they protect computer networks?

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.

24) What is the function of the OSI Session Layer?

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.

25) What is the importance of implementing a Fault Tolerance System?

A fault tolerance system ensures continuous data availability. This is done by eliminating a single point of failure.

26) What does 10Base-T mean?

The 10 refers to the data transfer rate. In this case, it is 10Mbps. The word Base refers to baseband, as opposed to broadband.

27) What is a private IP address?

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.

28) What is NOS?

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.

29) What is DoS?

DoS, or Denial-of-Service attack, is an attempt to prevent users from being able to access the Internet or any other network services. Such attacks may come in different forms and are 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.

30) What is OSI, and what role does it play in computer networks?

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.

31) What is the purpose of cables being shielded and having twisted pairs?

The primary purpose of this is to prevent crosstalk. Crosstalk’s are electromagnetic interferences or noise that can affect data being transmitted across cables.

32) What is the advantage of address sharing?

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.

33) What are MAC addresses?

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.

34) What is the equivalent layer or layers of the TCP/IP Application layer in terms of the OSI reference model?

The TCP/IP Application layer has three counterparts on the OSI model: 1) Session Layer, 2) Presentation Layer, and 3) Application Layer.

35) How can you identify the IP class of a given IP address?

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.

36) What is the main purpose of OSPF?

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.

37) What are firewalls?

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.

38) Describe star topology

Star topology consists of a central hub that connects to nodes. This is one of the easiest to set up and maintain.

Star TopologyStar Topology

Advantages:

Here are pros/benefits of start topology:

Disadvantages:

Here are cons/drawbacks of using Star:

39) What are gateways?

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.

40) What is the disadvantage of a star topology?

One major disadvantage of star topology is that once the central Hub or switch gets damaged, the entire network becomes unusable.

41) What is SLIP?

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.

42) Give some examples of private network addresses.

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

43) What is tracert?

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.

44) What are the functions of a network administrator?

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.

45) What is the main disadvantage of a peer to peer network?

Accessing the resources that are shared by one of the workstations on the network takes a performance hit.

46) What is a Hybrid Network?

A hybrid network is a network setup that makes use of both client-server and peer-to-peer architecture.

47) What is DHCP?

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.

48) What is the main job of the ARP?

The main task of the ARP or Address Resolution Protocol is to map a known IP address to a MAC layer address.

49) What is TCP/IP?

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.

50) How can you manage a network using a router?

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.

51) What protocol can be applied when you want to transfer files between different platforms, such as UNIX systems and Windows servers?

Use FTP (File Transfer Protocol) for file transfers between such different servers. This is possible because FTP is platform-independent.

52) What is the use of a default gateway?

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.

53) What can be considered as good passwords?

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.

54) What is the proper termination rate for UTP cables?

The proper termination for unshielded twisted pair network cable is 100 ohms.

55) What is netstat?

Netstat is a command-line utility program. It provides useful information about the current TCP/IP settings of a connection.

56) What is the number of network IDs in a Class C network?

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.

57) What happens when you use cables longer than the prescribed length?

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.

58) What common software problems can lead to network defects?

Software related problems can be any or a combination of the following:

59) What is ICMP?

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.

60) What is 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.

61) What is peer to peer?

P2P NetworkP2P Network

Peer to peer (P2P) are networks that do not rely on a server. All PCs on this network act as individual workstations.

62) What is DNS?

DNS is the Domain Name System. The main function of this network service is to provide host names to TCP/IP address resolution.

63) What advantages does fiber optics have over other media?

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.

64) What is the difference between a hub and a switch?

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

65) What are the different network protocols that are supported by Windows RRAS services?

There are three main network protocols supported: NetBEUI, TCP/IP, and IPX.

66) What are the maximum networks and hosts in class A, B, and C network?

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

67) What is the standard color sequence of a straight-through cable?

Orange/white, orange, green/white, blue, blue/white, green, brown/white, brown.

68) What protocols fall under the Application layer of the TCP/IP stack?

The following are the protocols under the TCP/IP Application layer: FTP, TFTP, Telnet, and SMTP.

69) You need to connect two computers for file sharing. Is it possible to do this without using a hub or a router?

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.

70) What is ipconfig?

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.

71) What is the difference between a straight-through and crossover cable?

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.

72) What is the client/server?

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.

73) Describe networking.

Networking refers to the interconnection between computers and peripherals for data communication. Networking can be done using wired cabling or through a wireless link.

74) When you move the NIC cards from one PC to another PC, does the MAC address gets transferred as well?

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.

75) Explain clustering support

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.

76) Where is the best place to install an Anti-virus program?

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.

77) Describe Ethernet

.

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.

78) What are some drawbacks of implementing a ring topology?

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.

79) What is the difference between CSMA/CD and CSMA/CA?

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.

80) What is SMTP?

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.

81) What is multicast routing?

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.

82) What is the importance of Encryption on a network?

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.

83) How are IP addresses arranged and displayed?

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

84) Explain the importance of authentication.

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.

85) What is meaning by tunnel mode?

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.

86) What are the different technologies involved in establishing WAN links?

87) Explain Mesh Topology

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 TopologyPartially Connected Mesh Topology

Full Mesh Topology: In this topology, every node or device are directly connected with each other.

Fully Connected Mesh TopologyFully Connected Mesh Topology

88) When troubleshooting computer network problems, what common hardware-related problems can occur?

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.

89) How can you fix signal attenuation problems?

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.

90) How does dynamic host configuration protocol aid in network administration?

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.

91) Explain profile in terms of networking concepts

Profiles are the configuration settings made for each user. A profile may be created that puts a user in a group, for example.

92) What is sneakernet?

Sneakernet is believed to be the earliest form of networking wherein data is physically transported using removable media, such as disk, tapes.

93) What is the role of the IEEE in computer networking?

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.

94) What protocols fall under the TCP/IP Internet Layer?

There are 4 protocols that are being managed by this layer. These are ICMP, IGMP, IP, and ARP.

95) When it comes to networking, what are rights?

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.

96) What is one basic requirement for establishing VLANs?

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.

97) What is IPv6?

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.

98) What is the RSA algorithm?

RSA is short for the Rivest-Shamir-Adleman algorithm. It is the most commonly used public-key encryption algorithm in use today.

99) What is mesh topology?

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.

100) what is the maximum segment length of a 100Base-FX network?

The maximum allowable length for a network segment using 100Base-FX is 412 meters. The maximum length for the entire network is 5 kilometers.

101) What is the 5-4-3 rule, and in which architecture is it used?

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.

102) What is the difference between TCP and UDP?

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.

103) What are the important elements of the protocol?

Here, are three most important elements of the protocol:

104) What is the maximum segment length of a 100Base-FX network?

The maximum length for a network segment using 100Base-FX is 412 meters.

105) What is a Decoder?

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.

106) What is Brouter?

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.

107) How to use VPN?

By using a Virtual Private Network (VPN), users can connect to the organization’s network. Corporate companies, educational institutions, government offices.

108) Why the standard OSI model is known as 802.xx?

The OSI model was started in February 1980. In 802.XX, ’80’ stands for the year 1980, and ‘2’ represents the month of February.

109) What is NVT (Network Virtual Terminal)?

NVT is a set of pre-defined rules to very simple virtual terminal interaction. This terminal helps you to start a Telnet session.

110) What is the source route?

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.

111) Explain the term Pipelining

Pipelining describes the sequencing of processes. When any new task begins before an ongoing task is finished, it is called sequencing.

112) Which measurement unit is used to measure the transmission speed of Ethernet?

The transmission speed of Ethernet is mostly measured in Mbps.

113) What is the maximum length of Thinnet cable?

The length of the Thinnet cable is 185 meters.

114) Which cable is also called as the RG8 cable?

Thicknet cable is also called as the RG8 cable.

115) Is coaxial cable still used in the computer network?

No, Nowadays, coaxial cable no longer used in a computer network.

116) Which cable uses the RJ11 connector?

Most of the telephone cable uses the RJ11 connector.

117) Explain Multi-homed Host

It is a host that has multiple network interfaces that multiple IP addresses is called a Multi-homed Host.

118) Explain EGP

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.

119) Explain the term Passive Topology

When a computer in the network listen and receive the signal, they are called passive topology.

120) What is the use of a Pseudo TTY?

It is a false terminal which allows you external machines to connect through Telnet or log in. Without this, no connection can take place.

121) Explain Redirector

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.

122) What Is TCP Three-Way Handshake?

TCP Three-Way HandshakeTCP 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.

123) What is a Hamming code?

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.

124) What is the Application of Hamming code?

Here are some common applications of using Hemming code:

125) What are the benefits of the Hamming code?

Here, are important benefits of Hamming code

126) What is a MAC Address?

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.

127) Why Use MAC Address?

Here are the important reasons for using MAC address:

128) What are the types of MAC Addresses?

Here are the important types of MAC addresses:

129) What are the important differences between MAC address and IP address

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.

130) What is an Analog Signal?

https://www.guru99.com/images/2/030720_0729_AnalogvsDig1.pngAnalog 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.

131) What is a Digital Signal?

Digital SignalDigital 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.

132) What are the differences between analog and digital signal?

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.

133) What is MAN?

MAN networkMAN 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.

134) What is Modem?

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.

ModemModem

135) What are the advantages of a Modem?

Here, are pros/advantage of Modem:

These interview questions will also help in your viva(orals)

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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.

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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

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

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.

Ring network topology

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)

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

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 - Networking Interview Questions

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.  

How does a firewall work - Networking Interview Questions

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?