Joe’s Tech Interview Questions

I’ve been in tech for a long time and have interviewed quite a bit from small to very large companies. All of the questions mentioned on this page are ones I have been asked for IT-related positions. Each time a question was asked, I’d write it down. I thought I would share these with all of you for those who are wanting to study for their next interview. Enjoy! —

User says their internet is slow and that it takes ages to get to websites. What steps would you do to troubleshoot?
Tell me five ways to find the current date and time on a Linux system.
How would you delete a file called -f on a Linux system?
Can you explain the difference between a hub, a router, and a switch.
What are the layers of the OSI model and describe each one?
How would you find a device on a network?
How does traceroute work? How is it different from ping?
What is ping?
Draw an entire network (very broad, but will allow you to show everything you know about one)
What is DHCP? How does it work? What is assigned to the computer that requested an address?
What is ARP?
How does a switch work?
What are some ways you can kill a program that is not responding? (think of the command line as well)
On a Linux machine, how would you find the drive you just plugged in? How would you mount it?
With the kill command what does -9 do (kill -9)? How is it different than kill -11?
What is DNS?
On a mac, what are some ways you can transfer data from one computer to another?
What is the PRAM and SMC reset do? What do each reset?
Say that I opened my browser and went to www.google.com. Describe what exactly happens in order for the page to display in my browser? In detail: https://github.com/alex/what-happens-when
What is an inode? What metadata does it contain?
What is the difference between a hard link and a soft link (symlink)?
What is the Windows registry? How does linux do the same thing? Mac?
What is the bootup process of a machine of your choice?
What are the differences between 802.11 a,b,g, and n?
What is in an IP header? TCP Header?
What is the difference between a public IP and a private IP?
What port is SMTP? Is there more than one port used for SMTP?
What is an MX record?
Describe the TCP Handshake
What is the difference between TCP and UDP?
A user has a machine that shows no output on the monitor. How to you troubleshoot? How can you see the state of the boot sequence without replacing the graphics card?
How do you define the following types of malware: a worm, a trojan, a rootkit?
How are ICMP packets denoted in the IP header? How are ICMP echo and reply denoted?
What routing protocol do you think Google uses and why?
You have 2 linux machines. How would you copy host A’s disk0 to host B’s disk1 and verify it copied correctly?
A user with a Windows laptop says that whenever they try to visit a particular website they instead see some strange Russian website they’re not expecting. How would you troubleshoot this?
In linux, you want to unmount a filesystem but it is in use. Can you fix this without rebooting the machine?
What is RAID? Describe RAID 0, 1, 5, 6, and 10
Your machine needs to send data to a host with an IP address on the same LAN. How does it specify the address the data should go to?
Be prepared to talk about any acronyms you mention
How do you start a website using Apache? Nginx?
You are a new consultant at a company and you are to give the company new internet. What up and down speeds would you provide and why?
What is OWFS?
What is Journaling? Why is it useful?
What is HTTPS? How does it work?
How do private and public keys work?
Does DNS use TCP or UDP? Why?
What is QoS?
What is a VLAN?
What is TLS?
What is ICMP?
What is a fork bomb?
How would you test if a port is open on a remote server?
You opened a port on a server, but from the outside, you cannot connect to that port. What might the problem be?
A fellow technician says that a Windows machine they’re working on has an IP address of 169.254.101.6, and asks you to help him troubleshoot. What do you do?
What are IPTables? What are the different things you can do with them?
On a Linux machine, how can you spin up a webserver? What is a vhost? Where do the configuration files live?
Name a few HTTP requests.
List some ports and define what they are used for.
What command would you use to list the number of threads for a running process?
How would you find the system load average WITHOUT causing more load?
What are some of the default Linux system variables?
What is garbage collection?
Using bash, how would you output a specific column in a file?
What’s the difference between bootp and DHCP?
What is Immutable Infrastructure? How does it differ from Mutable Infrastructure and what are some advantages of having an Immutable Infrastructure?
Name a few data structures.
What tool would you use to sniff DNS traffic?
What tool would you use to view disk IO?
What is a CDN?
What is Puppet, Ansible, Chef, Saltstack and what are they used for?

Joseph Ziegler

Joe's Tech Interview Questions