- Using the OSI model, which layer has the responsibility of making sure that the packet gets where it is supposed to go?
- What is the subnet mask, network address and broadcast address for the following address: 123.65.47.62/22?
- What command is used to show all open ports and/or socket connections on a machine?
- What is NAT? What is it used for?
- Which IP ranges/subnets are “private” or “non-routable” (RFC 1918)?
- What is a packet filter and how does it work?
- What is a proxy and how does it work?
- What is ARP and what is it used for?
- What is the difference between TCP and UDP?
- What command is used to show the route table for a machine?
- Explain asynchronous routing?
- What is the purpose of a default gateway?
- A TCP connection on a network can be uniquely defined by 4 things. What are those things?
- When a client running a web browser connects to a web server, what is the source port of the connection?
- What is the destination port of the connection?
- What is SMTP?
- What is an SMTP relay?
- Give the basic scenario of how a mail message is delivered via SMTP
- What function does DNS play on a network?
- What is an A record?
- What is an NS record?
- What is an MX record?
- What is a PTR record?
- What is a DNS forwarder?
- What command is used to lookup DNS records?
- What is meant by “Reverse Lookup”?
- What is LDAP and what is it used for?
- What is a DN in LDAP?
- What is SSH?
- What is SSL?
- What is IDS?
- What is IPS?
- What is the difference between IDS and IPS?
- What is meant by the term “DOS Attack”?
- What is RAID?
- What is swap and what is it used for?
- What command will show the available disk space on the Unix/Linux system?
- How do you determine the public and prive IP addresses, if applicable, of a Unix/Linux system from the command line?
- What Unix/Linux command will alter a file’s ownership?
- What Unix/Linux command will alter a file’s permissions?
- What Unix/Linux command will show all processes running on a system?
- What Unix/Linux command will show the details of a file(permissions, size, timestamp)?
- What Unix/Linux command would you use to list all currently loaded kernel modules?
- What command would you use to telnet to port 7777 on a machine with IP address 10.10.10.128?
- What Unix/Linux command(s) will show a system’s current resource allocations?
- What is the Unix/Linux command to remove a directory and its contents?
- What is the name and location of the system log on a Unix or Linux system?
- What would you do to recover a lost the root password to a Unix/Linux system?
- What is the difference between hardlink and symlink?
- What happens when you remove the source to a symlink?
- What are some of the security risks of symlinks?
- Explain a hardlink
- Where is a filename stored?
- What happens when a hardlink is removed
- how do you know when a file is removed
- Write a locking function in bash
- What is a pre-emptive kernel, what does that mean to you?
- What is an atomic operation?
- How does a switch get a mac address?
- What type of packet to discover a router?
- How does traceroute work?
- A careless sysadmin executes the following command:
chmod 444 chmod– what do you do to fix this?
I’m a DevOps/SRE/DevSecOps/Cloud Expert passionate about sharing knowledge and experiences. I have worked at Cotocus. I share tech blog at DevOps School, travel stories at Holiday Landmark, stock market tips at Stocks Mantra, health and fitness guidance at My Medic Plus, product reviews at TrueReviewNow , and SEO strategies at Wizbrand.
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