Top 20! Network Administrator Job Interview Questions
- Can you tell us about yourself?
This question is the most important not only because it’s the very first question of your interview but the only opportunity to sell yourself as the best candidate for this job. You have to make sure that this answer is tailored to the position at hand; meaning only talk about yourself in the relevance to this position. Talk about your past experience in IT and stay away from irrelevant personal stuff. Stick to that fact about yourself because if you say something that is not true, the interviewer may follow up with a question that you can’t answer.
2 What is a Firewall?
The firewall prevents the connection between two or multiple sources; it basically blocks any incoming or outgoing traffic.
Firewalls can be in software or hardware forms.
3 What is TCP/IP?
TCP is a Transmission Control Protocol that deals with establishing a connection between computers before any data is being sent; in other words, it acts as the highway for data packets being sent back and forth used by various protocols like HTTP or FTP. TCP also sorts out data packet receive the order.
4 Can you explain the difference between HTTP and HTTPS?
HTTP stands for HyperText Transfer Protocol used by the majority of websites as means of transmitting website data and it allows for use of hyperlinks. This protocol mostly uses TCP port 80.
HTTPS is a secure version of HTTP that allows for identity verification and low-level encryption using TCP port 443.
- What is a proxy or proxy server?
Proxy deals with filtering network traffic in a sense of preventing access to certain websites and
Can even monitor user web activity. To put it simply, it can block certain websites from being accessed but it can also act as a measure of hiding the true origin in point of access.
Can you explain what UDP is?
UDP stands for User Datagram Protocol.
Unlike TCP, UDP is constantly broadcasting a connection signal which can allow for faster connection speed-with TCP you have to wait for connection confirmation which takes time. UDP sends out data without consideration of what is receiving it; sort of like Radio signal.
- What is the loopback IP address?
The loopback IP address is 127.0.0.1.
As part of troubleshooting network connection issues; it is used to test the Network Interface Card for functionality. If you ping this IP address and it completes successfully it means your hardware is okay.
- What is DHCP?
DHCP stands for Dynamic Host Configuration Protocol.
The main function of DHCP is to handle the distribution of IP address on a network.
The IP address assigned by the DHCP server is “Dynamic”, meaning that they are leased and released dynamically.
To explain it further, if you connect a PC to a network it will get a leased IP address and if you disconnected or move the PC- it will be assigned a different one.
- What is FTP/ and port used?
FTP is a File Transfer Protocol used to transfer large files between computers with built-in ability to pause the transfer of data. Ports used by FTP are 20 and 21.
- What is SSH/ and port used?
Also known as Secure Shell; is used to establish a secure connection between devices that can by anything from computers to switches. For example; you can use SSH at a café and connect to any device anywhere; by establishing a configured Secure Shell tunnel between two devices.
Making the connection secure
- What is the maximum length of UTP cable allowed?
The maximum length of UTP is 90 to 100 meters for a signal segment connection.
If you have a switch or a repeater it can compensate for this limitation.
- What are the layers of the OSI model and how many?
There are 7 layers of OSI model: Physical Layer, Data Link, Network, Transport, Session, Presentation and Application.
- What is the job of a Network Layer?
A textbook answer for this question is; the Network Layer deals with routing, switching and transmitting of data from one point to another, but this layer is also responsible for error handling and packet sequencing.
- Can you name different types of network cables?
Cat-5 runs at 100Mb/s maximum, Cat-5e can run up to 1Gb/s, and Cat-6 can run up to 10Gb/s, connection speed. All cables are limited to 100 meters distance in order to run at optimum speed.
- What is Subnet Mask?
Subnet Mask dictates the size of a network and also tells which part of the subnet our host IP address belongs to. Basically you can have multiple subnetworks for the given IP address range.
- Can you tell me the difference between a Workgroup and a Domain?
With a Workgroup, you have a collection of systems that are connected to the same network but have their own set of rules and permission set at the local level. With a Domain, you have a group of systems that are bound by the rules of the centralized authentication server. In a Domain, each system has to connect through the Domain server using provided credentials.
- How would you determine the connection path between localhost a server?
A “TRACERT” command is used to accomplish this test. Similar to the “ping” command with the addition of letting us visualize which routers or switches are used to connect in reaching of our destination. Used for troubleshooting dead connections.
- Can you explain IPCONFIG?
IPconfig command is used to determine TCP/IP settings, DHCP configuration, DNS, Default Gateway, and Subnet Mask. It can also be used to change Local DHCP settings; for example, ipconfig /release and /renew
- What is a VPN?
A Virtual Private Network allows users to create a secure connection over a public network such as the internet. This is commonly used by mobile workers in order to access the company’s network from remote locations.
- Why should we hire you?
Just as important as the very first question on this list; this is your last chance to tell this employer why you are the best choice for this position. You should talk about your experience and how you could use that to benefit the company. Don’t be afraid to exalt yourself without coming off as egocentric; be polite and smile.
As bonus advice; before going for an interview make sure you do research about the company you have an interview with. The main reason for this is multiple interviews in which one of them may be with human resources.
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