init

This is an initiatian subject that will give you the opportunity to discover basic system and network commands. You can find the subject here

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Mandatory part

V.1 Let’s be friends

• Follow Slash16 on Facebook, Twitter and Linkedin

V.2 Network

• 1. Get the list of the network interfaces of the machine without displaying any detail for these interfaces. Only the list of names.
• 2. Identify and display the Ethernet interface characteristics:
  • (a) Identify broadcast address
  • (b) Identify all IP addresses which are part of the same subnet
• 3. Identify the MAC address of the Wi-Fi card
• 4. Identifiy the default gateway in the routing table
• 5. Identify the IP address of the DNS that responds to the following url: slash16.org
• 6. Get the complete path of the file that contains the IP address of the DNS server you’re using
• 7. Query an external DNS server on the slash16.org domain name (ie. : google 8.8.8.8)
• 8. Find the provider of slash16.org
• 9. Find the external IP of 42.fr
• 10. Identify the network devices between your computer and the slash16.org domain
• 11. Use the output of the previous command to find the name and IP address of the device that makes the link between you (local network) and the outside world
• 12. Find the IP that was assigned to you by dhcp server
• 13. Thanks to the previous question and the reverse DNS find the name of your host
• 14. What file contains the local DNS entries?
• 15. Make the intra.42.fr address reroute to 46.19.122.85

V.3 System

• 1. In what file can you find the installed version of your Debian?
• 2. What command can you use to rename your system?
• 3. What file has to be modified to make it permanent?
• 4. What command gives you the time since your system was last booted?
• 5. Name the command that determines the state of the SSH service.
• 6. Name the command that reboots the SSH service.
• 7. Figure out the PID of the SSHD service.
• 8. What file contains the RSA keys of systems that are authorized to connect via SSH?
• 9. What command lets you know who is connected to the System?
• 10. Name the command that lists the partition tables of drives?
• 11. Name the command that displays the available space left and used on the system in an humanly understandable way
• 12. Figure out the exact size of each folder of /var in a humanly understandable way followed by the path of it.
• 13. Name the command that find, in real time, currently running processes
• 14. Run the ‘tail -f /var/log/syslog‘ command in background
• 15. Find the command that kills the background command’s process
• 16. Find the service which makes it possible to run specific tasks following a regular schedule
• 17. Find the command that allows you to connect via ssh on the VM. (In parallel with the graphic session)
• 18. Find the command that kills ssh service
• 19. List all services which are started at boot time and name this kind of services
• 20. List all existing users on the VM
• 21. List all real users on the VM
• 22. Find the command that add a new local user
• 23. Explain how connect yourself as new user. (With graphic session and ssh session)
• 24. Find the command that list all packages

V.4 Scripting

• 1. Write a script which displays only the login, UID and Path of each entry of the /etc/passwd file.
• 2. Write a script which delete an ACTIVE user on the VM.
• 3. Three’s a Charm. Write a script of you choice.

References

• Find IP address in Linux command line How to See All Devices on Your Network With nmap on Linux How to List/Get/Display/Find MAC Address in Linux Using 11 Popular Methods The Host Default Gateway and Routing Table How to Install and Use dig and nslookup Commands in Linux Linux find DHCP server IP address using CLI

Kisses and chocolates