An introduction to Networks and Systems Administration
All the commands used in this project are uploaded in this repository.
They are sorted in 3 domains, following the subject: Network, System, Scripts.
A unique document has been created for this project.
In this rare document you can follow the subject with a reminder for all notions learned, but also explanations for each scripts and commands.
It has been designed to be very complete in terms of informations, and represents dozens of hours of research and writing.
It takes the form of a tutorial of 75 pages, allowing you to be guided step by step and to complete the project from A to Z.
It can be shared upon request.
I would like to thanks a lot the 42 peers (and friends) who helped me to produce this document: Hugo D., Julia A. and Julien B.
Unfortunately only French is available for now, the content is organised as below:
Check the operation (status) of a service
Help with the “service” command
List all installed services
Enable a service
Disable a service
Reset a service (stop then restart)
Install a package
Delete a package
Delete a package with all its dependencies
Also delete all config files (purge)
Delete all installer packages
Update all packages
Update a specific package
Basic commands
System commands
Network commands
Configuration files
Install VirtualBox
Install a VM in VirtualBox
Install Debian in the VM
What to do once Debian is installed
VM storage
01 Get the list of the network interfaces of the machine without displaying any detail for these interfaces (only the list of names)
02 Identify the IP address of the Ethernet interface
XX Display only the IP address of the Ethernet interface
XX Display the Broadcast address of the Ethernet interface
XX Display all the IP addresses that are part of the same subnet
03 Identify the MAC address of the Wi-Fi card
04 Identifiy the default gateway in the routing table
05 Identify the IP address of the DNS that responds to the following url: slash16.org
06 Get the complete path of the file that contains the IP address of the DNS server you’re using
07 Query an external DNS server on the slash16.org domain name (ie. : google 8.8.8.8)
08 Identify the host provider for the Slash16 website
09 Identify the public IP address 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 Check that the server with the 10.51.1.253 IP address is reachable from your computer
XX Identify the server type for 10.51.1.253 IP address
XX Identify the IP address assigned to you by the DHCP server
13 Use the reverse DNS to find out the name of the server linked to the 10.51.1.81 IP address
XX With the result of the previous question and the reverse DNS, find the name of your host
14 What file contains the local DNS entries
15 Make the 46.19.122.85 address reroute to intra.42.fr
01 In what file can you find the installed version of your Debian
02 What command can you use to rename your system
03 What file has to be modified to make it permanent
04 What command gives you the time since your system was last booted
05 Name the command that determines the state of the SSH service
06 Name the command that reboots the SSH service
07 Figure out the PID of the SSHD service
08 What file contains the RSA keys that are authorized to connect via SSH
09 What command lets you know who is connected to the System
10 Name the command that lists the partition tables of external devices
11 Name the command that displays the available space left on the system
12 Figure out the exact size of each folder of /var
13 Name the command that find 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 which gives the list of firewall rules
18 With the previous command, authorize only IP addresses from 10.0.0.0/8 to connect to your system
19 With the previous command, forbid all others IP
XX Command which, in parallel with the graphical session, allows you to connect to the machine with SSH
XX Command to stop the SSH service
XX List the services that start automatically when the machine boots and give the name of this type of service
XX List all existing users on the machine
XX List all real users of the machine
XX Command to add a new local user
XX Explain how to log in as this new user (in graphical session and in ssh session)
XX Command that lists all the packages INSTALLED on the machine
01 Write a script which displays only the login, UID and Path of each entry of the /etc/passwd file
02 Write a script which updates all the package sources, then all the packages, and then logs everything in a file named /var/log/update_script.log
Create a scheduled task for this script, once per week at 4 AM
03 Write a script which displays the list of files from the folder given as parameter, sorted by size
04 Write a script which monitors the modifications made to the /etc/crontab file and sends an e-mail to root if the file is modified
Create a scheduled task to run this script everyday at midnight
05 Write a script which displays 42
XX Write a script that allows you to delete a LOGGED user on the machine
XX Never two without three
XX Start a new 42 project
There is a new version of the subject and some adjustment has been made with the objectives (02 03 etc).
Objectives marqued as 'XX' are from new subject and are also explained completely in the document.
The updated document, including old and new objectives, is available in French only and can be shared upon request.
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