Linux Server - Home Server - Raspberry Pi


Copyright:	© 2022 VEXIT , Tomorow is today ® , www.vexit.com
Author:	Vex Tatarevic
Date Created:	2022-11-23

Definitions

In this book we will use technical words that you may not be familiar with.

Below is a table explaining these words.


Client	Your personal computer: Windows, Mac or Linux, that you use to connect remotely to home server
Server	Computer that we are using as a home server machine
Directory	Folder
Machine	Computer
Terminal	Program used for inputing commands to interact with operating system. On Windows we use Git Bash terminal program. On Linux and macOS, terminal program is called Terminal

Obtain Static IP Address from ISP

By default, your ISP (internet service provider) will assign your local network a Dynamic IP Address - which keeps on changing all the time.

In order for your server computer to be reachable from outside world (by other computers on the internet), it must have a Static IP Address.

Contact your ISP and ask them to upgrade your internet connection plan to one that provides a Static IP Address

Install Client Software

Log into your Client computer. This is the computer you use every day. We will use this computer to connect remotelly to our server at the later stage.

Install Git Bash

On your Client computer
Open the browser and go to git-scm.com.
Download and install Git

Install Telnet

On Windows: - Open Control Panel - Click on Programs - Click on Turn Windows features on or off - Check the box next to Telnet Client - Click OK - Telnet is now installed

On macOS: - Open Terminal: CMD + Space > type Terminal > Enter - Install Telnet

  brew install telnet

If you don't have brew installed, go to brew.sh and follow the instructions to install it.

On Linux: - Open Terminal: CTRL + ALT + T - Install telnet

  sudo apt install telnet

Prerequisites

Buy a Raspberry Pi computer. Go to Raspberrypi.com for more info.
Buy Micro SD card of minimum 32 Gb memory size
SSD (solid state drive) disc for storage (ideally 2 terabytes), but for practice you can even use a USB drive
Why choose Raspberry Pi ?
Small - It is the smallest server computer in the world. It is only the size of your palm
Portable - If there's a flood, fire, war, earthquake or any kind of disaster happens around you and you need to quickly move, you simply unplug your Raspberry Pi, put it in your pocket and run. It's that simple.
Reliable - you can simply plug it in the power, leave it there and forget about it. You can turn the power on or off in the wall whenever and it will not affect the Pi. The Pi just keeps running.
Low power consumption - It uses very little electricity. It costs only $5 per year to run it 24/7.

Install Raspberry Pi OS

Download and Install Raspberry Pi OS

On your Client computer
Go to Raspberry Pi OS download page: www.raspberrypi.org/software
Download and install "Raspberry Pi Imager"
This program is used to install the operating system onto the MicroSD Card
Plug the Micro SD card into your Client PC.
If you don't have a Micro SD card slot on your computer, you will have to use MicroSD to USB adapter.
Run the "Raspberry Pi Imager" program:
- Under Operating System, Click "CHOOSE OS"
- Select "Raspberry Pi OS (other)"
- Scroll down and select "Raspberry Pi OS (64-bit)" - A port of Debian Bullseye with the Raspberry Pi Desktop
- Under Storage, Click "CHOOSE STORAGE", then select your SD card
- Click "WRITE" and wait for the process to complete
Remove the MicroSD card from your PC and insert it into your Raspberry Pi
Connect keyboard, mouse and monitor to Server (Raspberry Pi).
Turn on the Server
You will see the first screen of the setup wizard with the text:

Welcome to the Raspberry Pi Desktop!

IMPORTANT: If you are using Bluetooth keyboard and mouse, make sure to put them in pairing mode on the very first screen of the setup wizard and wait for the Connect popup to come up. Do not progress to the next wizard screen until your keyboard has been connected, because you will not be able to type in the text or connect the keyboard at the later screens.

Walk through installation wizard by clicking Next
On Set Country screen:
Set your Country and Timezone
Check Use English language
Check use US keyboard
On Create User screen, set traditional default username and password :
Username: main-user
Password: main
You may get the warning popup

You have used a known default value for the username or password. We strongly recommend you go back and chose something else.
Don't wory about this. We will change the username and password later.
On Select WiFi Network screen, select your wireless network from the list and provide password so that server computer can connect to the internet.
On Update Software click Next to download the latest software.
At the end of the wizard you should be prompted to restart the computer.
After the computer restarts, you will see the Desktop with the menu at the top.

Change Boot Mode

Raspberry Pi computer can boot in one of 2 modes:

Desktop Boot - computer runs in graphic user interface mode.
CLI Boot - computer runs only in command line interface mode and you cannot access any graphic user interface.

It is highly recommended to use Desktop Boot mode, because it is easier to use and you can use comand line interface by opening Terminal program.

Changing to CLI-Only Boot Mode

Use this option only if
you want to use Raspberry Pi computer as a headless server (without monitor, keyboard and mouse) - in this case probably you will be using SSH to connect to your server remotely from another computer, so better wait until you set up SSH connection before changing to CLI-Only Boot mode.
you want to save resources by not running Desktop interface
you are comfortable using command line interface only.
Click on : Start (Top-Left Raspberry Pi Icon) > Preferences > Raspberry Pi Configuration
Change the setting Boot to 'To CLI' and click OK
Click Menu > Shutdown > Reboot , to restart the computer
The computer should restart and you will see the command line prompt:

main-user@raspberrypi:~ $ _

Changing to Desktop Boot Mode

sudo raspi-config > System Options > Boot / Auto Login > Desktop > OK > Reboot

In the next section read in more detail instructions on how to open and use raspi-config.

Open/Close raspi-config

Raspi-config is Raspberry Pi Configuration Tool.

Open raspi-config - type in the following command

sudo raspi-config
Use the up and down arrow keys to move the highlighted selection between the options available. Pressing the right arrow key will jump out of the Options menu and take you to the < Select > and < Finish > buttons. Pressing left will take you back to the options.
If arrows do not work, then use the Tab key to move from one section to another.
Close raspi-config
Hit ESC key

OR - Move to < Finish > and hit Enter

Change Keyboard Layout

YOU CAN SKIP

NOTE: You can skip this section and go to Change Autologin to Require Login because you have already configured keyboard to "use US keyboard" in the Setup Wizard. This "Change Keyboard Layout" section was for the users who were installing Raspberry Pi from old command line interface installation and is no longer relevant.

By default Raspberry Pi uses English (UK) keyboard layout which has a problem with displaying pipe symbol "|" in a standard way. It instead displays tilde symbol "~".
Because we need "|" (pipe symbol) for some of the commands, we will change keyboard layout to standard US keyboard layout.

NOTE: If you are using Desktop view and you get problems with navigating to Keyboard layout via Terminal CLI, you can do it via Desktop menu instead: - Start > Preferences Keyboard and Mouse > Keyboard > Keyboard Layout > Model: Generic 105-key PC (intl.) > Layout English (US)

To configure Keyboard in CLI (command line interface): - Open raspi-config - Select: 5 Localisation Options > L3 Keyboard - Use Down Arrow to move down to "5 Localisation Options", then hit Enter key - Use Down Arrow to move down to "L3 Keyboard", then hit Tab key to focus on < Select > button, then hit Enter key to select

You should see Keyboard model page with Generic 105-key PC selected
Hit Enter to continue to Keyboard layout
On Keyboard layout it will have selected English (UK)
On Keyboard layout page scroll-down and select Other
Select English (US) > Hit Enter > Scroll-up > Select English (US) > Hit Enter
On the next pages hit Enter to select defaults, until you return back to main screen with System Options selected
Hit Tab 2 times to select Finish
Hit Enter to exit raspi-config
CTRL + L to clear the screen

By default your Raspberry Pi will be set to log you in automatically. This is unsafe. We want to change this so that login is required every time.

HINT: In command line interface you can select previously typed-in commands by hitting "UP-ARROW"

Open raspi-config
Select: System Options > Boot / Auto Login
If you are using Desktop interface : Select B3 Desktop > Hit Enter

OR
If you are using CLI interface : Select B1 Console > Hit Enter
You will be taken to main config screen
Hit Tab > Tab to select < Finish > button, then hit Enter
You should see "Would you like to reboot now?" . Select < Yes > and hit Enter

The computer will restart and then you will be presented with login interface.

Now Log in with: - Username: main-user - Password: main

Set up Wi Fi

YOU CAN SKIP

NOTE: You can skip this section as your WiFi has already been configured in the Setup Wizard.

Refs:
- Settig up WiFi: https://www.raspberrypi.org/documentation/configuration/wireless/wireless-cli.md
Open raspi-config

sudo raspi-config
Select: 5 Localisation Options > WLAN Country
- Select your country > Enter > Reboot
After reboot > log in > run : sudo raspi-config
Select: 1 System Options > S1 Wireless LAN > Enter SSID (means type-in WiFi name) > Hit Enter > Type-in WiFi password > Hit Enter > Hit Esc (to exit) > CTRL + L (to clear the screen)

Start Using Command Line Interface

CLI (Command Line Interface) - is a name for any command line program that accepts text input to execute operating system functions.

From this point on we will configure the system via command line interface.

Open Terminal with keyboard shortcut : CTRL + ALT + T
This will open the Terminal command line interface and you will see the command line prompt:

main-user@raspberrypi:~ $
You can now type the commands.
Close Terminal - type command exit to close the Terminal

Update and Upgrade system

YOU CAN SKIP

NOTE: You can skip this section as your system has already been updated and upgraded in the Setup Wizard.

Update system, type command:

sudo apt-get update
Upgrade system, type command:

sudo apt-get upgrade

Shut Down Safely

When turning off your Server, you should always shut down safely.

To safely turn off your Server, type in the following command

sudo shutdown -h now
The -h option will halt the working processes. If you remove -h from the above command, it will directly shutdown the Raspberry Pi without waiting for anything, which is not recommended.
To shut down after 10 minutes type

sudo shutdown -h 10
To cancel scheduled shutdown
```
shutdown -c
```

Configure the System

Refs:

Using Raspi Config: https://www.raspberrypi.org/documentation/configuration/raspi-config.md

Set up Wi-Fi

YOU CAN SKIP

NOTE: You can skip this WiFi setup section, because your Wi-Fi should have already been set in the Setup Wizard. This section shows you how to set up WiFi in the command line interface on any version of Linux operating system, including Raspberry Pi OS.

Get the name of wireless network interface

iwconfig

You should get something like:

lo        no wireless extensions.

eth0      no wireless extensions.

wlan0     IEEE 802.11  ESSID:"TPG-5G-1C2A"  
          Mode:Managed  Frequency:5.18 GHz  Access Point: 00:1C:2A:1C:2A:1C   
          Bit Rate=6 Mb/s   Tx-Power=31 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:on
          Link Quality=70/70  Signal level=-32 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

wlan0 - is the name of the wireless network interface.
ESSID (Extended Service Set Identifier) - is the name of your wireless network. In above example it is TPG-5G-1C2A
ESSID should be "off/any" if the wireless interface has not been activated yet.

Activate wirelessnetwork interface

sudo ifconfig wlan0 up
Connect to your wireless network using WPA (Wi-Fi Protected Access) encryption

sudo wpa_passphrase {{WIFI_NAME}} {{WIFI_PASSWORD}} > /etc/wpa_supplicant.conf
Replace {{WIFI_NAME}} and {{WIFI_PASSWORD}} with your actual WiFi name and password

Check that your WiFi details have been saved:

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

You should see

country={{YOUR_COUNTRY_CODE}}

network={
    ssid={{YOUR_WIFI_NAME}}
    psk={{YOUR_WIFI_PASSWORD}}
}

Reboot

sudo reboot
Check that you are connected to your WiFi

Enable/Disable root user

root account is a superuser account that exists in system by default and it can execute any priviledged actions without using prefix sudo.

It is not advisable to ever enable root account but there are some situation when we may need it.

Enable root

Log in as main-user
Enable "root" user

sudo passwd root
This will prompt you for password
Enter password root
Reboot (restart computer)

reboot
Log in with username root and password root

NOTE: If using the Dektop view, when you log in with root, you will not see the menu at the top. In this case, hit CTRL + ALT + T to open the Terminal. Now you will be able to execute the commands with root.

Execute priviledged command "apt-get update"

apt-get update
This time we did not have to use prefix sudo

IMPORTANT: Make sure to disable the root user after you complete priviledged actions available only to root user

Reboot computer

reboot

Disable root

Log in with non-root account
Disable root account

sudo passwd -l root
Restart computer

reboot

Change Username and Group Name

In this section we will change initially created username "main-user" and password "main" to our new username and password.

We cannot change username of main-user while logged in as main-user and the only other user in the system is super user account called root.

This is the only reason why we will enable user root in this unique situation. Normally root user should always be disabled and instead all the commands that require root priviledges, can be executed by prefixing them with keyword sudo.

After we are finished with executing priviledged actions using root account, we must disable the root account.

Log in as main-user
Enable root account and reboot

sudo passwd root sudo reboot
Log in as root
If in Desktop view : Open Terminal CTRL + ALT + T
Change username main-user to your desired username (We will call it "my-user" but you can call it whatever you like)

usermod -l my-user main-user

NOTE: THROUGHOUT THIS BOOK WE WILL REFER TO YOUR USERNAME AS "my-user". Replace all the occurences of my-user with your own personal username.
Change user's directory name to my-user

usermod -m -d /home/my-user my-user
Change user's group name to my-user

groupmod -n my-user main-user
Reboot

reboot
Log in as "my-user", with password "main"
Change password to a very strong password

passwd
Confirm that my-user account has sudo privileges, by running system update command:

sudo apt-get update
You will be prompted for password
```
[sudo] password for my-user:
```
Type in password to continue

NOTE: When we changed the username main-user to my-user, it has reset the way sudo behaves to default - asking for password every 15 minutes. In the next section we will configure sudo not to prompt my-user to enter password every time we want to run a priviledged command.

IMPORTANT: Disable root account

sudo passwd -l root

NOTE: From this point forward we will not use root account again.

Remove Sudo Password Prompt

When we want to run priviledged commands we type sudo before the command. For this to work, our user account must be a member of sudo group - which our default account is.

By default, using sudo asks for password every 15 minutes

To disable asking for sudo password, do the following:

Open sudoers file for editing using visudo command (visudo command is a safe and secure way of editing the /etc/sudoers file)

sudo visudo
Look for the line starting with %sudo. It should look like this:

# Allow members of group sudo to execute any command %sudo ALL=(ALL) ALL
Add keyword NOPASSWD and a column symbol before the last ALL. It should now look like this

# Allow members of group sudo to execute any command %sudo ALL=(ALL) NOPASSWD:ALL
Save and close the file: CTRL + S CTRL + X
Reboot and log in with my-user
Run update command to make sure you are not being prompted for password:

sudo apt-get update
You should NOT be prompted for password this time

Configure Users' Home Folder Security

When you create a new user in Raspberry Pi operating system, he can see all other users' folders by going inside /home folder.

Then a user can enter any other user's folder and read and execute any files.

This is not a very secure set-up for a serious multi user information system.

Let's demonstrate this insecure setup practically and then we will apply the fix to make it more secure.

Demonstrate System Insecurity

NOTE: You can skip to next section Fix System Insecurity . This section is just a demonstration for understanding of the problem.

Log in as my-user
Create a sample file inside user's home directory
Go inside user's home folder
```
cd ~/
```
Create file "my-secure-file.txt" in the root of my-user'shome folder
```
touch my-secure-file.txt
```
Open my-secure-file.txt in nano editor
```
nano my-secure-file.txt
```
Write inside it the text: "My secure content..."
Save and close the file: CTRL + S CTRL + X
Create user testuser

sudo adduser testuser
When prompted for password type "test"
For all other prompts hit Enter
On the last prompt "Is the information correct? [Y/n]" , type "y" and hit Enter
Reboot
Log in as testuser
Go inside /home folder

cd /home
List all the files and folders inside the /home

ls -l
You should see the folders: testuser, my-user

A secure system should not show other users' home folders

Attempt to navigate inside the folder of the user my-user that is not currently logged in and list the contents of that folder:

cd my-user ls -l
You should see a list of user's folders and a file my-secure-file.txt

A secure system should not allow access to files and folders of other users

Open file my-secure-file.txt

nano my-secure-file.txt
The file will be opened and you will see "My secure content..."

A secure system should not allow viewing the contents of other users' files

Clean up the test data:

Reboot the Server
Log in as my-user
Delete testuser account (if you have created it in previous section)

sudo userdel -r -f testuser
You will get a message "userdel: testuser mail spool (/var/mail/testuser) not found" . Don't worry about that message. It just means that there was no mail folder found when deleting this user.
The user has been deleted
Go inside the /home directory and list the contents. You will see that testuser folder has disappeared:

cd /home ls -l
Delete the temporary file "my-secure-file.txt" that we created

rm /home/my-user/my-secure-file.txt

In the next section we will fix the above system insecurities in a way that a security policy will be applied to any new users that get created in the system.

Fix System Insecurity

NOTE: We will use chmod command to change permissions on user folders. For now you don't need to understand how chmod works. We will explain this in the later sections.

There are 3 things we need to do to secure our system. Go ahead and do the following:

Hide all the folders inside the /home folder:

sudo chmod 701 /home
Users will now NOT be able to see other users' folders inside /home
Users will still be able to access other users' folders if they know the location of the folder e.g. /home/my-user. We will fix this in the next 2 steps
Change permissions on our user's folder, to prevent access by other users

sudo chmod 750 /home/my-user
Change the default permission assigned to user's folder automatically when user is created using adduser command. The default permission is 755 - means anyone can read and execute the files in any user's folder. We want to change it to 750 - means other users have no access to user's folder at all.
Open adduser.conf
```
 sudo nano /etc/adduser.conf
```
Scroll down to "DIR_MODE=0755" and change it to "DIR_MODE=0750"
Save and close the file: CTRL + S CTRL + X

Now only the owner of the folder and the group assigned to folder will be able to access it. All others will not be able to, unless of course they have root priviledges, then they can access it with "sudo".

CHROOT Jail

https://phoenixnap.com/kb/chroot-jail

https://www.tecmint.com/restrict-ssh-user-to-directory-using-chrooted-jail/

Create User Admin

In the previous sections we showed you how to change existing username and password.

Now we will learn how to create a priviledged account called admin.

IMPORTANT: Disable root account - in case you missed to do it before.

  sudo passwd -l root

NOTE: my-user is already a priviledged account, so we can execute any priviledged commands with my-user account by prefixing them with keyword sudo

Log in with my-user
Create user admin

sudo adduser admin
Provide password: admin and Full Name: Admin. For all other fields hit Enter to continue.
The last question of the user creation wizard will ask you if the information is correct. Type y and hit Enter.

You should see :

  Adding user `admin' ...
  Adding new group `admin' (1001) ...
  Adding new user `admin' (1001) with group `admin' ...
  Creating home directory `/home/admin' ...
  Copying files from `/etc/skel' ...
  New password:
  Retype new password:
  passwd: password updated successfully
  Changing the user information for admin
  Enter the new value, or press ENTER for the default
        Full Name []: Admin
        Room Number []:
        Work Phone []:
        Home Phone []:
        Other []:
  Is the information correct? [Y/n] y

IMPORTANT: You should create a strong password for your admin account. Password we are using here is just for practice.

NOTE: When you create user admin with adduser command, this will also create a group admin and a home directory /home/admin

Go inside /home and list the contents

cd /home ls -l

we will get a message:

ls: cannot open directory '.': Permission denied

This is because we configured our system, in the previous section, to hide user directories.
As a priviledged user we can still see users' directories by using sudo keyword
```
 sudo ls -l
```
You should see that a new directory admin has been created.
Try to enter into admin user's directory /home/admin

cd /home/admin

You will get a message

-bash: cd: /home/admin: Permission denied

Our security configuration works well. No user can enter inside the directory of the other user.
Give elevated priviledges to admin - assign admin user to the sudo group:

sudo usermod -aG sudo admin
The -aG flag stands for Append and Group. This command instructs usermod command to append the username to a group, which in this case is the sudo group.
Keyword sudo stands for: "superuser do"
You now have an admin account with sudo priviledges. This means that admin account can execute commands which require elevated root priviledges by prefixing those commands with keyword sudo.
Check what groups user admin is in

groups admin
You should get
```
admin : admin sudo
```
Reboot computer

NOTE: From this point forward we will only use admin account.

Change Computer Name

NOTE: THROUGHOUT THIS BOOK WE WILL REFER TO YOUR SERVER COMPUTER NAME AS "my-home-server". Wherever you see "my-home-server", replace it with the actual name of your home server machine.

Log in as admin
Change name in hostname file
Open file "hostname", located in the "/etc" directory, using nano editor
```
sudo nano /etc/hostname
```
Change the line of text that says "raspberrypi" to your desired computer name (e.g. "my-home-server").
Save and close the file: CTRL + S CTRL + X

nano - is a popular simple text editor used in Linux to edit text in files.

Change name in hosts file
Open file "hosts", located in the "/etc" directory, with nano
```
sudo nano /etc/hosts
```
Change the line of text that has your old computer name. It should be the last line that starts with 127.0.0.1
```
127.0.0.1       localhost
::1             localhost ip6-localhost ip6-loopback
ff02::1         ip6-allnodes
ff02::2         ip6-allrouters

127.0.1.1       old-computer-name
```
- Change old-computer-name to your new computer name (e.g. my-home-server)
Save and close the file: CTRL + S , CTRL + X
Reboot computer

sudo reboot
Log in with admin
Your command line prompt should now show

admin@my-home-server:~ $
Confirm hostname has been changed

hostname
- it should now say my-home-server

Set up Network

Check Local Network Connectivity

Ping the machine - Check that your computer is on the network using ping command

ping my-home-server.local
Hit CTRL + C to exit PING (Packet Internet Groper)

You should see lines of something like this repeating:

64 bytes from 192-168-1-105.tpgi.com.au (192.168.1.105): icmp_seq=1 ttl=64 time=0.102 ms

NOTE: 192.168.1.105 in this example is Server machine's IP address on your local network
Print internal IP address of this machine

hostname -I
You should see address like : 192.168.1.105
Print interface configuration

ifconfig
- You should see your Ethernet, loopback and wireless network interfaces: eth0, lo, wlan0

Open Router Admin

On your Client computer open any browser e.g. Chrome, and navigate to your local network router admin web-page by typing in the address bar the following url:
```
http://192.168.1.1
```
If that does not work, then try:
```
http://192.168.0.1
```
If that does not work, search on Google "what is router admin url for {{NAME_OF_YOUR_ROUTER_BRAND}}", for example "what is router admin url for tp-link"

Get Internal IP

In your Router Admin - Verify that the your server machine is visible on router admin website
You should see a link that says something like "Wireless Clients". It may say something different depending on your router brand.
On the list of connected wireless clients you should see a name of your Server computer ( e.g. my-home-server ) and its Internal IP Address next to it (e.g. 192.168.1.105)
Note down the Internal IP address of your Server machine. You will be using it in the next section to configure Port Forwarding.

Set up Static Internal IP

Internal IP addresses are not static. They get changed by the router's DHCP server.

DHCP (Dynamic Host Configuration Protocol) - is a protocol that provides quick, automatic, and central management for the distribution of IP addresses to devices on the network within a network. A DHCP server dynamically issues unique IP addresses to devices on the network and automatically configures other network information. In most homes and small businesses, the router acts as the DHCP server.

We need to make sure that our home server machine always has the same IP address on the local network (static IP) so that we can reliably connect to it.

In your router admin look for LAN Settings. For example on tp-link modem go to : Advanced > Network > Lan Settings
You should see sections: DHCP Server, Client List, Address Reservation
In Client List find your server computer and note it's MAC Address and Assigned IP for example 192.168.1.105
In Address Reservation section, click Add button which will prompt you to enter MAC and IP address.
Type in manually MAC and IP or click on button SCAN if available and select your device from list.
Click OK
Your server computer now has static internal IP and it will not be changed by DHCP server.

Get External IP

Open Router Admin
You should see the External IP address of your router on the main page of the router admin website. It should look something like this:

IP Address: 113.216.184.151

Configure Port Forwarding

SKIP this section if you do not want to open your server to Internet, but rather just want to access it from your local network. In this case go to section Set up Firewall.

NOTE: You can only do this if you have a Static External IP that your ISP has provided for you.

In order to access our Server from anywhere via internet, we need to first set up port forwarding on our router.

Port Forwarding - allows incoming connections from broader Internet (in technical terms known as WAN (Wide Area Network)) to reach a specific device/port on a LAN (Local Area Network). Port forwarding is achieved by using NAT (Network Address Translation) table that maps External Port to the Internal IP address.

On your Client computer, open the internet browser window and go to router admin webpage which should be located at url http://192.168.1.1/ or http://192.168.0.1/
Go to the page for port forwarding. It is different for different routers.
To find where the port forwarding settings are on your router => Search on the internet for keywords: "{{NAME_OF_YOUR_ROUTER_BRAND}} port forwarding", for example "tp-link router port forwarding"
Here is an example of port forwarding location for tplink router Archer VR1600v:
- On the main menu go to : Advanced > NAT Forwarding > Virtual Servers
- You should see :
- Buttons Add and Delete
- List of Virtual Servers with IPs and Ports

At this point we want to add a new virtual server that points to our SSH port accessing SSH program.

SSH (Secure Shell) is used to remotely execute commands on our home server in a secure way.

We will install SSH later.

Add new Virtual Server by clicking button Add
- Set Service Type to "SSH"
- Set External Port to number from 1024 to 49151
- Set Internal IP to your Home Server's IP address on the network e.g. 192.168.1.105
- Set Internal Port to default SSH port 22
- Set Protocol to "TCP"
Settings should look something like this:


Service Type:	SSH
External Port:	1234
Internal IP:	192.168.1.105
Internal Port:	22
Protocol:	TCP

Now you have forwarded External Port 1234 to machine on your network with Internal IP 192.168.1.105 and SSH program that is running on that machine's Internal Port 22.

This means that you can now access SSH on that machine from the remote computer via your home network's Static External IP e.g. 113.216.184.151 and External Port 1234.

We will explain later how to connect to your server remotely using SSH in SSH Setup Section.

Network Port - is a logical number that identifies to which local process or service, the specific incoming internet traffic should be directed towards.

Ports are classified into 3 main categories:

Well Known Ports - ( 0 - 1023 ) - are used by system or processes run by root or with specific privileges.

Registered Ports - ( 1024 - 49151 ) - are used by programs run by users in the system.

Dynamic Ports - ( 49152 - 65535 ) - are not assigned for any specific purpose.

Check Outside Connectivity

There are 2 ways to check network ports' outside connectivity. You should know both ways. - IsMyPortOpen.com - Netcat

Use IsMyPortOpen.com

Check if your server's ip and port is reachable from outside by using utility website ismyportopen.com

Go to http://ismyportopen.com/
Type in your IP and port and hit button Check
You should get a green check and a message : Port is open

Use Netcat

On Mac OS Install Homebrew first - If you are on Mac OS make sure to install homebrew first. Go to: https://brew.sh/ for more info.
Open Terminal

Run command

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

Add homebrew to your PATH. NOTE: replace admin with your username:

(echo; echo 'eval "$(/opt/homebrew/bin/brew shellenv)"') >> /Users/admin/.bash_profile

eval "$(/opt/homebrew/bin/brew shellenv)"

Install Netcat on your client computer


Windows	Go to: https://nmap.org/download.html
Mac OS	Run command: brew install netcat
Linux	Run command: sudo apt install netcat

Check on your client computer if you can connect from outside to your server computer ip and port e.g. 113.216.184.151:8333
On Linux and Mac OS run
```
nc -zv 113.216.184.151 1234
```
On Windows open command prompt and run
```
ncat -zv 113.216.184.151 1234
```

Set up Firewall

Firewall - is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It restricts internet traffic in to, out of, or within a private network. Firewall functions by selectively blocking or allowing data packets. Its purpose is to prevent anyone inside or outside of a private network from engaging in unauthorized web activities.

UFW - Uncomplicated Firewall is a standard CLI program for working with the firewall on Linux.

Install and Enable UFW

NOTE: Make sure you are logged in physically on the server machine and not remotely(e.g. via SSH). This because if you enable firewall remotely, you will be disconnected from the server and will not be able to connect again until you disable firewall or add a rule to allow the port on which remote connection program connects to the server (e.g. port 22 for SSH).

Install ufw

sudo apt install ufw
Check status:

sudo ufw status

You may get

ERROR: Couldn't determine iptables version

OR

Status: inactive

Reboot:

sudo reboot
Check status again: sudo ufw status
This time you should get: Status: inactive
Enable firewall:

sudo ufw enable

You should see

Firewall is active and enabled on system startup

Check existing firewall rules (list of allowed ports)

sudo ufw status
You should see: Status: active
This means that firewall is active and running but has no rules yet. You have to add rules to allow ports.

We will first add a rule for SSH port because in the next section we will enable SSH on the server.

Add Firewall Rule

Add port 22 - the standard port for SSH (Secure Shell) connections, which is how we will connect to our server remotely.

sudo ufw allow 22
Add another port 1234

sudo ufw allow 1234
Show firewall status

sudo ufw status

You should see

Status: active

To                         Action      From
--                         ------      ----
22                         ALLOW       Anywhere
1234                       ALLOW       Anywhere
22 (v6)                    ALLOW       Anywhere (v6)
1234 (v6)                  ALLOW       Anywhere (v6)

Reboot

sudo reboot

Remove Firewall Rule

Display a numbered list of rules

sudo ufw status numbered

You should see something like

     To                         Action      From
     --                         ------      ----
[ 1] 22/tcp                     ALLOW IN    Anywhere
[ 2] 1234                       ALLOW IN    Anywhere
[ 3] 22/tcp (v6)                ALLOW IN    Anywhere (v6)
[ 4] 1234 (v6)                  ALLOW IN    Anywhere (v6)

Remove port 1234 by rule number

sudo ufw delete 2
NOTE: When you remove the rule, the number position of all rules after it , decreases by one
Display numbered list again

sudo ufw status numbered

You should now see

     To                         Action      From
     --                         ------      ----
[ 1] 22                         ALLOW IN    Anywhere
[ 2] 22 (v6)                    ALLOW IN    Anywhere (v6)
[ 3] 1234 (v6)                  ALLOW IN    Anywhere (v6)

Remove port "1234 (v6)" by rule number

sudo ufw delete 3

SSH - Remote Connect

Ref: https://www.raspberrypi.org/documentation/remote-access/ssh/

SSH (Secure Shell) - is a cryptographic network protocol for operating network services securely over an unsecured network. Typical applications include remote command-line, login, and remote command execution, but any network service can be secured with SSH.

In order to connect to our Server remotely (from the Client computer), we need to enable SSH on the Server.

Step 1 - Enable SSH

Log into the Server with admin user.
Enable SSH with Linux commands

sudo systemctl enable ssh sudo systemctl start ssh
Confirm that SSH is active

sudo systemctl status ssh

You should see a green dot and a text like

ssh.service - OpenBSD Secure Shell server
    Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)
    Active: active (running) ...
    ...

Step 2 - Remote Connect with SSH

We can connect remotely from another machine on our Local Network (LAN) or from the Internet (WAN).

SSH over LAN

To connect over LAN we need to get Server's Internal IP and Internal Port

Open Router Admin
Get Internal IP of your server e.g. my-home-server

SSH over Internet

To connect over Internet we need to get Server's External IP and External Port

Log into the Client computer (your personal computer)
Open Router Admin - in the browser go to url http://192.168.1.1/ or http://192.168.0.1/
Get the IP Address - You should see your network's IP Address on the first page of your router admin. This is the static internet address assigned by your Internet Service Provider.
Get the port of the Server machine - The port should be the same as the one you configured in the section Configure port forwarding e.g. 1234
Suppose that we are using the following details

Port 1234

Username admin

IP 113.216.184.151
Open Git Bash or Terminal
Connect to the Server - connect remotely to the Server using ssh command

ssh -p {{EXTERNAL_PORT}} {{USERNAME}}@{{IP_ADDRESS}}

For example:

ssh -p 1234 admin@113.216.184.151

You will get this message

The authenticity of host '[113.216.184.151]:1234 ([113.216.184.151]:1234)' can't be established.
ED25519 key fingerprint is SHA256:1f8b2ad4be0e47c9b52ce4af6c652663.
This key is not known by any other names
Are you sure you want to continue connecting (yes/no/[fingerprint])?

Enter yes to continue. You will get something like this

Warning: Permanently added '[113.216.184.151]:1234' (ED25519) to the list of known hosts.

You may (or may not) get disconnected with this message
```
Connection closed by 113.216.184.151 port 1234
```
- In this case, just enter ssh connect command again
  
  ssh -p 1234 admin@113.216.184.151
You should see a password prompt

admin@113.216.184.151's password:
After you type in the correct password, you will be remotely logged into the Server
You can do everything on SSH remote connection as if you were logged in on the physical server computer. You should see a command line prompt like this:

admin@my-home-server:~ $
Disconnect from the Server : Hit CTRL + D
From this point onwards you can use your Client PC to access the Server and run all the commands on it.
- Therefore you can disconnect monitor and keyboard from the Server computer if you wish so.

NOTE: On your Client computer, ssh has created a dot directory called .ssh inside the user home directory - To see the hidden .ssh directory, open terminal and type in this command

  ls -la

Go inside the .ssh folder and view contents of it

cd .ssh ls -l
You should see the file called known_hosts
Open known_hosts

nano known_hosts
You should see something like:

[113.216.184.151]:1234 ssh-ed25519 jfY8xUO1cfDAlbbB ... [113.216.184.151]:1234 ecdsa-sha2-nistp256 FUbUx1a3sM= ...
These are identifying keys related to your Server. If you connect to any other servers, similar keys will be added to this file to mark those servers/hosts as known hosts.

Step 3 - Passwordless Connect with RSA

RSA (Rivest-Shamir-Adleman) encryption - is a public-key encryption used for securing data transmission of e-mail and other digital transactions over the Internet. "RSA" is the acronym for the surnames of Ron Rivest, Adi Shamir and Leonard Adleman, who publicly described the algorithm in 1977.

SSH protocol uses RSA encryption to enable Client computer to connect remotely to Server computer by use of public and private key, instead of having to type in the password.

SSH files are stored inside ".ssh" folder located in the User Home directory.

Let's suppose that we have the following client-server set-up:
Client computer:

Client Machine Name my-pc

Operating System Windows

Username Admin

User directory C:\Users\Admin\
- Replace Admin above with your username
Server computer:

Server Machine Name (hostname) my-home-server

Operating System Raspberry Pi OS

Username admin

User directory /home/admin/
- Replace my-home-server above with your server name
On the Client open Git Bash or Terminal
Create RSA encryption keys on Client using ssh-keygen command:

ssh-keygen
You should see a prompt:
```
Generating public/private rsa key pair.
Enter file in which to save the key (/c/Users/Admin/.ssh/id_rsa):
```
The prompt gives a suggestion to use a default file called id_rsa inside .ssh/ folder to store the private key.

However this is not good enough for us. We want to structure our files with the view that we will connect to many other servers.
Copy the suggested file path (/c/Users/Admin/.ssh/id_rsa) and append the Server name at the end like:
```
/c/Users/Admin/.ssh/id_rsa_my-home-server
```
Hit Enter
Next you should see passphrase prompts. Just hit Enter without typing in any text.

Enter passphrase (empty for no passphrase): Enter same passphrase again:

The keys will be generated and you will see the following output (where "my-pc" is the name of your Client computer, "Admin" is your username on your Client computer,"my-home-server" is your Server computer name):

Your identification has been saved in /c/Users/Admin/.ssh/id_rsa_my-home-server
Your public key has been saved in /c/Users/Admin/.ssh/id_rsa_my-home-server.pub
The key fingerprint is:
SHA256:h7FUEfiH8PtvNANPjc7uZM1VH6pGG/5LmI/PNp83M6E Admin@my-pc
The key's randomart image is:
+---[RSA 3072]----+
|         .+o     |
|        o.       |
|        o+ .   +.|
|       . ++ o + =|
|        S .= B  o|
|         .+ * B+.|
|           O ++o+|
|          . BEo+o|
|           .oX*o=|
+----[SHA256]-----+

Copy the public key to the Server using ssh-copy-id command. Type in the following command. (Replace the tokens - words starting with {{ and ending with }} - with your own data)

ssh-copy-id -i ~/.ssh/id_rsa_{{SERVER_NAME}}.pub -p {{SERVER_PORT}} {{SERVER_USERNAME}}@{{SERVER_IP_ADDRESS}}

For example:

ssh-copy-id -i ~/.ssh/id_rsa_my-home-server.pub -p 1234 admin@113.216.184.151
- NOTE: Path "~/" is a short notation for your user home directory path e.g. "/c/Users/Admin/"
- You will be prompted for password:
  
  /usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/c/Users/Admin/.ssh/id_rsa_my-home-server.pub" /usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed /usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys admin@113.216.184.151's password:
- After you type in the password you will see output:
  
  Number of key(s) added: 1
  
  Now try logging into the machine, with: "ssh -p '1234' 'admin@113.216.184.151'" and check to make sure that only the key(s) you wanted were added.
- NOTE: logging into the Server machine by using command "ssh -p 1234 admin@113.216.184.151" will still ask us for password. This is because we have not created our RSA keys in the default file "id_rsa" but instead we have created it in the custom file named "id_rsa_my-home-server". Therefore we need to specify the location of the key file when using ssh to connect, for example: "ssh -i ~/.ssh/id_rsa_my-home-server -p 1234 admin@113.216.184.151"
Connect to the Server without a password

ssh -i ~/.ssh/id_rsa_my-home-server -p 1234 admin@113.216.184.151
NOTE: We are using the path to file "id_rsa_my-home-server" and NOT "id_rsa_my-home-server.pub" (private key, not public key).
This time, you should be logged into Server without a password prompt
View public key on Server (for the purpose of understanding the private-public key handshake)
Navigate to .ssh folder on the server
```
cd ~/.ssh
```
- View contents of the folder
  
  ls -l
- You should see one file "authorized_keys"
Open authorized_keys file
```
nano authorized_keys
```
You will see inside the file authorized_keys, the copied public key from the Client that looks like "ssh-rsa VMXfGsZk9MmnTFvkwSZ11O ..."
This is how Server authorizes Client connection - by making sure that the public RSA key matches the one stored in authorized_keys file.
Exit nano editor : CTRL + X

As you can see, eventhough we now don't need to provide the password, it is still cumbersome to type in all the connection data every time we want to connect to the Server.

In the next section we will learn how to connect to the Server by just providing the Server name in ssh command like: "ssh my-home-server".

Disconnect from the Server : CTRL + D
Clean the terminal window : CTRL + L

Step 4 - One Word Connect with SSH Config

On the Client, go into .ssh folder:

cd ~/.ssh
Create file "config" without any file extension

touch config
Open file config

nano config
Paste into it Host connection configuration like:

Host {{SERVER_NAME}} HostName {{SERVER_IP_ADDRESS}} Port {{SERVER_PORT}} User {{SERVER_USERNAME}}

For example:

Host my-home-server HostName 113.216.184.151 Port 1234 User admin IdentityFile ~/.ssh/id_rsa_my-home-server
Save and exit nano editor : CTRL + S CTRL + X
Connect to Server

ssh my-home-server
You should be automatically logged into Server without password prompt

RDP - Remote Connect - Windows

NOTE: This section is relevant only to Windows client computer.

RDP (Remote Desktop Protocol) is a proprietary protocol developed by Microsoft which provides a user with a graphical interface to connect to another computer over a network connection.

If we want to access remotely graphical user interface (GUI) of our server, from Windows personal computer, we can use Remote Desktop Connection program that comes pre-installed on Windows.

But first we need to install program called xrdp on the Linux home server and then we can connect to it from our Windows computer. Ref: http://www.xrdp.org/

Configure XRDP on Server

Open terminal on your Client and SSH into your server machine

ssh my-home-server
Update and upgrade packages

sudo apt update sudo apt upgrade
Install xrdp

sudo apt install xrdp
Check status of xrdp service

sudo service xrdp status

You should see something like

● xrdp.service - xrdp daemon
   Loaded: loaded (/lib/systemd/system/xrdp.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2023-09-04 22:55:13 BST; 4min 18s ago
     Docs: man:xrdp(8)
           man:xrdp.ini(5)

XRDP listens on port 3389, so you will need to open that port on your firewall.

Allow port 3389 in your firewall

sudo ufw allow 3389
Get your server's IP address and note it down

hostname -I
NOTE: this will give you internal IP address of your server on your local network. If you want to connect to your server from outside your local network, you will need to get your external IP address. See section Get External IP for more info.

Connect from Client

On your Windows computer, open Remote Desktop Connection program
You can find it by typing "Remote Desktop Connection" in the search bar at the bottom left of your screen
Or you can find it in the Start Menu under Windows Accessories folder
In the Remote Desktop Connection window, type the IP address of your server and click Connect
You will get a warning message about certificate. Click Yes to continue
You will get a login screen. Enter your username and password and click OK
You should be logged in and see the desktop of your Linux server on the screen of your Windows computer

That's it. Now you can use your Linux server's GUI from your Windows computer, from anywhere in the world.

Upload / Download

Upload

Copy file from local windows computer to Raspbery Pi server

scp -P {{SERVER_SSH_PORT}} {{CLIENT_FILE_PATH}} {{USERNAME}}@{{SERVER_IP_ADDRESS}}:/{{SERVER_FILE_OR_FOLDER_PATH}}

Example: from directory of the source files

scp -P 1234 file1.json admin@220.237.80.202:/home/my-files/
scp -P 1234 file2.json file3.txt admin@220.237.80.202:/home/my-files/

Example: from any directory using full path

scp -P 1234 /C/my-files/file1.json admin@220.237.80.202:/home/my-files/
scp -P 1234 /C/my-files/file2.json /C/my-files/file3.txt admin@220.237.80.202:/home/my-files/

Download

Copy file from Raspbery Pi server to local windows computer

Manage External Storage Device

Refs:
- Raspberry Pi - External Storage Config

Ubuntu.com - Fstab

Temporary Storage

Turn on your server machine in Desktop mode (not headless mode) - it should already be set up in Desktop mode
Insert external storage device into your server computer
On Raspberry Pi you will get popup that says "Removable medium is inserted." Click OK
Open file explorer
You should see your external drive mounted on the left panel inside directory "/media/{{USERNAME}}".

For example: "/media/admin/2.1 TB Volume"

By default, Linux mounts external drives onto /media/{{USERNAME}} folder.

In file explorer there is a quick access link to your external drive on the left panel. - On Linux Mint it is under the "Devices" section - On Raspberry Pi it is at the top of the left panel under the Home Folder and Filesystem Root

You should see a name of your external drive for example "123 GB Volume".

Now you can use your external drive as a temporary storage for your files.

Permanent Storage

In this section we are going to learn how to mount an external drive on the selected directory of our Server machine so that we can use it as a permanent storage for our data.

We will reformat the drive to use ext4 file format which is Linux's file format that allows us to set permissions on files and folders for multiple users - same as for the rest of the files on our Server machine.

We will configure the server to automatically mounts our storage when machine is rebooted.

Prepare External Storage device. It can be one of these 3:


1.	HDD (Hard Disk Drive)	Cheap, spacious and slow. Old spinning disc technology
2.	USB (Flash Drive)	Small, portable and quick (prefered is USB 3 which is quicker and larger than USB 2)
3.	SSD (Solid State Drive)	Best performance, large storage, most expensive. Best option.

Plug your external storage device into your Server
NOTE: if using USB 3, you should plug it in the port that has a BLUE colored line

In order to properly administer user permissions on the external drive, we need to reformat it into EXT4 format.

ext4 (fourth extended filesystem) - is the default file system for Linux.

Step 1. Create Partition

Get external drive partition: sudo blkid
- Your external drive details will look something like:
  
  /dev/sda1: UUID="5C24-1453" BLOCK_SIZE="512" TYPE="exfat" PARTUUID="00000000-01"
- If you are not sure which one on the list is your drive's block device info , then unplug the external drive and run the blkid command again. The one that is missing from the list is your external drive.
- Note down these details:
  
  device name /dev/sda1
  
  device id UUID="5C24-1453"
  
  device type TYPE="exfat"
Start disk format:

sudo fdisk /dev/sda1 --wipe auto

You will get warning in red like this:

The device contains 'exfat' signature and it will be removed by a write command. See fdisk(8) man page and --wipe option for more details.

Just ignore it

You will see a prompt: Command (m for help):
Type g and hit Enter - to create a new empty GPT partition table
You will see message like Created a new GPT disklabel (GUID: aa60d5a8-6a7f-43f6-8c41-8958ae018526).
You may see a warning in red - just ignore it
You will get a prompt: Command (m for help):
Type n and hit Enter - to create a new partition on the disk
You will get a prompt: Partition number (1-128, default 1):
Hit Enter to accept default value
You will get a prompt: First sector (2048-1953525167, default 2048):
Hit Enter to accept default value
You will get a prompt: Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-4095997918, default 4095995903):
Hit Enter to accept default value
You will get message like: Created a new partition 1 of type 'Linux filesystem' and of size 1.9 TiB.
You will get a prompt: Command (m for help):
Type w and hit Enter - to write table to disk and exit
You will get message like: The partition table has been altered.

NOTE: You may get this error message or messages:

Failed to add partition 1 to system: Invalid argument

OR

Calling ioctl() to re-read partition table.
Re-reading the partition table failed.: Invalid argument

AND

The kernel still uses the old table. The new table will be used at the next reboot.
Syncing disks.

Just ignore above messages
Reboot

sudo reboot
Run sudo blkid again
Your external drive details should now look like this:

/dev/sda1: PTUUID="aa60d5a8-6a7f-43f6-8c41-8958ae018526" PTTYPE="gpt" PARTUUID="eb3cd722-01"

Step 2. Format Partition

To format partition:

sudo mkfs.ext4 /dev/sda1
You will get:

Found a gpt partition table in /dev/sda1 Proceed anyway? (y,N)
Type y, hit Enter and WAIT !!!
NOTE: Creating journal may take a long time especially if you have a large disk (terabytes in size). So BE PATIENT AND DON'T TOUCH ANYTHING until it's finished. Go and grab a coffee while you wait ;-)

You will see output like:

Creating filesystem with 15155195 4k blocks and 3792896 inodes
Filesystem UUID: aa60d5a8-6a7f-43f6-8c41-8958ae018526
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624, 11239424

Allocating group tables: done
Writing inode tables: done
Creating journal (65536 blocks): done
Writing superblocks and filesystem accounting information: done

You will know it's finished when you see the last line:

Writing superblocks and filesystem accounting information: done
Run command to check block ids again

sudo blkid
It should now look like this:

/dev/sda1: UUID="aa60d5a8-6a7f-43f6-8c41-8958ae018526" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="eb3cd722-01"

Step 3. Mount External Drive

To start using our external drive, we first need to mount it.

Mounting - is the act of associating a storage device to a particular location in the directory tree. Unix systems have a single directory tree. All accessible storage must have an associated location in this single directory tree.

"/dev/" directory - contains files that represent devices that are attached to the local system. These are not regular files that a user can read and write to. These files are called devices files or special files.

blkid command - displays information about available block devices e.g. external hard drives or USBs. blkid without any argument will list all the available devices with their Universally Unique Identifier (UUID), the TYPE of the file system, and the LABEL if it's set.

NOTE: We will refer to your external storage device as "my-drive". You can replace this with your own name.

We will have to create a directory onto which we will mount our external drive.

NOTE: Standard practice is to create mount directory inside "/mnt/" directory. However, you can create it anywhere you like and it will still work.

Create mount directory

sudo mkdir /mnt/my-drive
Get device id

sudo blkid
Mount external drive by pointing device id to mount directory

sudo mount /dev/sda1 /mnt/my-drive
Unmount the external drive

sudo umount /mnt/my-drive

Manually mounting external drive that we want to use as permanent storage is not practical. We want to set it up to automatically mount on the same folder every time Server machine starts up.

To automatically mount external drive we need to add entry to /etc/fstab file.

FSTAB (File System Table) file - is a system configuration file that contains information about disk partitions and other devices that are mounted after the system boots.

To understand persistent mounting of file system in more details check out Redhat - Persistently mounting file systems

For the full description of fstab file syntax, see FSTAB File Syntax in the Appendix.

You can also check out Ubuntu.com - Fstab for more detail info about fstab.

Run command to check block ids again

sudo blkid
Find your external drive in the list (normally starts with /dev/sd...)
Write down 3 things
UUID
TYPE
mount directory path

For example:

UUID 5C24-1453

TYPE exfat

MOUNT_DIR_PATH /mnt/my-drive
Open the fstab file for edit

sudo nano /etc/fstab
Add the following line at the bottom of fstab file
```
UUID={{UUID}} {{MOUNT_DIR_PATH}} {{TYPE}} defaults,auto,users,rw,nofail 0 0
```
- Replace tokens {{UUID}}, {{MOUNT_DIR_PATH}} and {{TYPE}} with the data you noted above in the previous step.
For example:
```
UUID=aa60d5a8-6a7f-43f6-8c41-8958ae018526 /mnt/my-drive ext4 defaults,auto,users,rw,nofail 0 0
```
- Save and exit nano editor : CTRL + S CTRL + X
Restart the Server machine

sudo reboot

Now your Server should automatically mount the external drive when you start the Server machine.

You should not unplug this drive. This is our main storage device.

If you want to unplug the external drive that has been mounted, you should unmount it first.

#### Step 4. Test Auto Mounting

If after reboot you get a black screen with a long message that contains "Root account locked" got to section Troubleshoot Mounting to fix it. The solution is in Fixing Error - Root account locked section.

Otherwise continue with steps bellow

Check your mount directory to see if the external drive has been mounted

ls -l /mnt/my-drive
You should see "lost+found" directory inside your mount directory like:
```
total 0
drwxr-xr-x 2 root root 0 Sep  5 00:00 lost+found
```
If you cannot see the folder "lost+found" inside your mount directory, then your external drive has not been mounted successfully. Proceed to next checks.
Check fstab file to see if the UUID, mount directory path and type are correct. First runn blkid to get your drive details.

sudo blkid sudo nano /etc/fstab
UUID must match the UUID of your external drive e.g. UUID=aa60d5a8-6a7f-43f6-8c41-8958ae018526
Mount directory path must match the mount directory path you created e.g. /mnt/my-drive
File System Type must match the file system type of your external drive e.g. ext4
Check journal logs for mount directory /mnt/my-drive

journalctl -u mnt-my-drive.mount -b
Slashes in mount directory path are escaped with dashes. So if your mount directory path is "/mnt/my-drive" then you need to type "mnt-my-drive.mount" in the command above.
-b - filters out entries for last boot. If you dont't use -b , you will see a journal log for the whole journal of mounting onto directory /mnt/my-drive

If mount was succesfull journal log should show you something like this

Dec 08 12:44:33 my-home-server systemd[1]: Mounting mnt-my-drive.mount - /mnt/my-drive...
Dec 08 12:44:34 my-home-server systemd[1]: Mounted mnt-my-drive.mount - /mnt/my-drive.

If mount failed, you may see this error in journal logs

mount: /mnt/my-drive: wrong fs type, bad option, bad superblock on /dev/sda1, missing codepage or helper program, or other error.

If journal logs show that the boot failed and you can see "bad superblock error":

mount: /mnt/my-drive: wrong fs type, bad option, bad superblock on /dev/sda1, missing codepage or helper program, or other error.

Then you need to run file system check for your external drive.

Run fsck (file system check) command on the external drive

sudo fsck /dev/sda1
Say yes to all prompts
Reboot the Server machine

sudo reboot
Check journal logs again

If your external drive has not been mounted again and you got the bad superblock error again, chances are that your external drive is corrupte and not fixable. In this case you just have to get a new external drive.

Check that files and directories persist

Create files and directories inside your mount directory

sudo touch /mnt/my-drive/test.txt  \
&& sudo mkdir /mnt/my-drive/test  \
&& sudo touch /mnt/my-drive/test/test2.txt

Reboot the Server machine
```
sudo reboot
```

List the files in your mount directory

ls -l /mnt/my-drive \
&& ls -l /mnt/my-drive/test

You should see the files and directories you created before reboot

total 20
drwx------ 2 root root 16384 Dec  8 11:10 lost+found
drwxr-xr-x 2 root root  4096 Dec  8 13:12 test
-rw-r--r-- 1 root root     0 Dec  8 13:12 test.txt
total 0
-rw-r--r-- 1 root root 0 Dec  8 13:12 test2.txt

If you cannot see the files and directories you created before reboot, then your external drive has not been mounted successfully. Proceed to next checks.
If you have problems with booting or auto mounting, go to section Troubleshoot Mounting

Step 5. Give Access

Give all access to group admins (read, write, execute)

setfacl -m ""g:admins:rwx" /mnt/my-drive

Unmount

Make sure you are not inside the directory that you are trying to unmount. So if you are inside the directory, you need to go out of it first:

cd ~

For this exercise we will rename the directory "my-drive" to "myDrive" to demonstrate unmounting but we will rename it back to "my-drive" after that.

Try to rename mount directory from my-drive to myDrive

sudo mv /mnt/my-drive /home/myDrive

You will get this message

mv: cannot move '/mnt/my-drive' to '/home/myDrive': Device or resource busy

This is because your external drive is mounted onto this directory

In this situation we need to unmount the external drive.

Unmount the external drive

sudo umount /mnt/my-drive
Rename mount directory from my-drive to myDrive

sudo mv my-drive myDrive
List home directories

ls -l /home/
You will see that the directory my-drive has been changed to myDrive
If you wanted this directory to be mounted automatically, you would have to change the line of text inside the file "/etc/fstab" to use new directory name for example:
```
UUID=5C24-1453 /home/myDrive exfat defaults,auto,users,rw,nofail 0 0
```
And then you would have to reboot the server computer
However we will not be changing the name of the drive. This was just for practice.
Change back the name of the drive to my-drive

sudo mv /home/myDrive /mnt/my-drive
Make sure that file "/etc/fstab" contains the correct file path "/mnt/my-drive", for example:

UUID=5C24-1453 /mnt/my-drive exfat defaults,auto,users,rw,nofail 0 0

NOTE: When you use sudo mv to rename the directory, the group and the owner of the directory will change to root. You need to change this back to your user e.g. admin

sudo chown admin /mnt/my-drive 
sudo chgrp admin /mnt/my-drive

Dealing with 'target is busy'

If you cannot unmount external drive because of the persisting 'target is busy' message, then continue to read this section to fix it.

The 'target is busy' message means there are files on the storage device that are in use by a program. To close the files, use the following procedure.

Close any program which has open files on the storage device.
If you have a terminal open, make sure that you are not in the folder where the storage device is mounted, or in a sub-folder of it.
If you are still unable to unmount the storage device, you can use the lsof tool to check which program has files open on the device. You need to first install lsof using apt:

sudo apt update sudo apt install lsof
To use lsof:

lsof /mnt/my-drive

Assign access only to our user

We will temporarily allow access to external-drive only to our user:

sudo chown $(whoami):$(whoami) -R /mnt/my-drive
- The $(whoami) variable will take the value of the user you are currently logged in as e.g. admin

Troubleshoot Mounting

FIXING ERROR Root account locked

You reboot Raspberry Pi after having changed /etc/fstab to auto-mount your external drive.

You get the black screen with a long mesage:

You are in emergency mode. After logging in, type "journalctl -xb" to view system logs, "systemctl reboot" to reboot, "systemctl default" or "exit" to boot into default mode.

Cannot open access to console, the root account is locked.
See sulogin(8) man page for more details.

Press Enter to continue.

Turn off your RaspberryPi
Take out the Micro SD that OS is installed on
Put the SD into your personal computer (Windows, Mac etc.)
Go inside the SD boot disk and find file cmdline.txt and open it
Add the following to the end of the text on the same line, separating it with space
```
init=/bin/sh
```
Eject the SD card
Put the SD card back into Raspberry Pi and turn the Pi on.
This time the Pi will start in command line mode and take your commands input.
Raspberry pi SD card has two main partitions, since we cannot read the partition table directly you must manually locate the device for your root and boot partitions and mount them.
To do this

ls /dev
You should see mmcblk0p1 & mmcblk0p2. The second device mmcblk0p2 will be your root partition. You need to remount this with read write permissions.
```
mount -o remount,rw /dev/mmcblk0p2 /
```
Open fstab
```
nano /etc/fstab
```
- Remove the line for mounting your external drive. Use CTRL + K to delete the whole line.
Turn off Raspberry Pi by turning off power or pulling out the power cable
Put the SD card back into your PC and open cmdline.txt file again
Lastly we need to revert cmdline.txt to original state (remove the temporary init=/bin/sh we added to it).
Now put SD card back into Pi and turn it on. The Pi will boot normally this time

FIXING ERROR Failed to mount

If you rebooted your Pi and your USB disc is not mounted.

For example you see red line in boot progress text:
```
[FAILED] Failed to mount /mnt/my-drive.
```
OR
Or you log in and notice that /mnt/my-drive does not contain files
Then you try to manually mount it and you receive error:

mount : /mnt/my-drive : wrong fs type, bad option, bad superblock on /dev/sda1, missing codepage or helper program, or other error.
You can check report of what happened by running
```
journalctl -u mnt-my-drive.mount -b
```
- Slashes in mount directory path are escaped with dashes. So if your mount directory path is "/mnt/my-drive" then you need to type "mnt-my-drive.mount" in the command above.
- Option -b is just for last boot. Omit that if you want the whole journal for mounting your external drive
- Hit CTRL + C to exit journal logs

FIX 1. - Change mount option for check fylesystem during boot

Open fstab
```
sudo nano /etc/fstab
```
Change mount mapping for your external drive to use flags "1 1" instead of "0" at the end. For example:
```
UUID=aa60d5a8-6a7f-43f6-8c41-8958ae018526 /mnt/my-drive ext4 defaults 1 1
```
Reboot

FIX 2. - Format and Partition USB disc in Desktop GUI with GParted

Change to Desktop boot
```
sudo raspi-config
```
- System Options > Boot > Desktop
Reboot
Install GParted - tool for disc partitioning. Open Terminal at the top menu and type command
```
sudo apt install gparted
```
Open GParted: Start Menu > System Tools > GParted
Select your device from dropdown list in top right. Should be something like: /dev/sda (1.91 TiB)
- This will display your disk below
Delete old partition:
- Right-click on partition > Delete
- This will display : "Delete pending" at the bottom . Ignore that and continue
Create new parition:
- Right-click on partition > New
- "Create new Partition" window will pop-up
- Leave all the defaults
- Select File system: ext4
- Click Add
- popup will close and you will see green tick at the top
Click on green tick at the top
- You will get warning : "Are you sure you want to apply the pending operations?"
- Click Apply
- Wait for operations to complete
Get your USB drive's UUID from the list of blocks
```
sudo blkid
```
Open fstab
```
sudo nano /etc/fstab
```
Edit the line for your external drive mount or add it if it doesn't exist already:
```
UUID=aa60d5a8-6a7f-43f6-8c41-8958ae018526 /mnt/my-drive ext4 defaults 1 1
```
- NOTE: UUID should be changed to the one you noted previously, after running blkid command
- NOTE: flags "1 1" at the end. That's very important. They mean that on startup should : 1 = Dump, 1 = Check filesystem for errors.
- With 1 1 flags set Raspberry Pi will take long time to start about 5 to 10 minutes because it will be doing a file system check. However this is necessary if you have a large USB 1 terabite or more.
Save

FIXING Long Boot - Checking in progress

After you have enabled auto mounting your external drive, your server machine may be taking very long time to boot, especially if your external drive is large e.g. terabytes in size.

You may get this message on boot Checking in progress on 1 disk (1.0% complete)
The Problem:

fsck is supposed to only run only when it needs to: either the filesystem wasn't cleanly unmounted or "it's been a while since it ran". The filesystem records the timestamp of when it was last unmounted for that second reason.

The pi doesn't have a real time clock, though. This doesn't matter if you're connected to the internet because of NTP. Otherwise it will just default to 1/1/1970 12:00 AM UTC (or some hardcoded time in kernel) on every boot.

So during boot (without ntp, the date is set back 1970), it looks at the current ridiculously current time, which is "before the last unmount date". Linux fscks just to be on the safe side in this insane situation. From its point of view, the FS was last unmounted "in the future".

There's already a workaround this: a service called fake-hwclock which keeps the time going forward by auto saving and loading from a file. It's enabled by default. The problem with it is that the boot order is such that often the fsck part is run before the system time is restored by fake-hwclock.
The Solution:

Fix the boot order. Configure systemd so that fake-hwclock runs before the fsck.

Create /etc/systemd/system/fake-hwclock.service.d/fsck.conf

sudo mkdir /etc/systemd/system/fake-hwclock.service.d
sudo touch /etc/systemd/system/fake-hwclock.service.d/fsck.conf
sudo nano /etc/systemd/system/fake-hwclock.service.d/fsck.conf

Edit fsck.conf - add following lines

[Unit]
Before=systemd-fsck-root.service

Reboot

Optional Installation

Add Support for 32 bit programs on 64 bit OS

When we try to run programs created for 32 bit system on our 64 bit Raspberry Pi OS, it will not work.
We recommend adding support for 32 bit programs as some software providers still haven't upgraded their products to support 64 bit Raspberry Pi OS
For example, in the next optional section - Install and Run VPN - we will be installing Express VPN but at the current time ExpressVPN only has installation for 32 bit Raspbery Pi OS.

To provide support for 32 bit programs run the following commands one by one:

sudo dpkg --add-architecture armhf

sudo apt-get update

sudo apt-get install libc6:armhf libstdc++6:armhf

cd /lib
sudo ln -s arm-linux-gnueabihf/ld-2.23.so ld-linux.so.3

NOTE: There is a downside to this approach - after adding armhf you have to be careful when installing new packages that you get the 64 bit version if available and don't end up installing 32bit packages that you don't need.

Express VPN

Optionally you may install VPN (Virtual Private Network) to ensure your privacy on the internet.
VPN effectively masks your IP address and geographical location.
Open account with any VPN provider. We recommend ExpressVPN
You need to download and install VPN client on your Pi. We will describe here how to do it with ExpressVPN. But you can also follow steps provided by ExpressVPN at : https://www.expressvpn.com/support/vpn-setup/app-for-raspberry-pi/

1. Download Express VPN

Open Git Bash terminal on your PC and connect to your Pi.

Create download directory where you will download expressvpn. This should be inside your mounted USB directory. Suppose your USB drive is mounted on /mnt/my-drive then run this command:

   sudo mkdir -p /mnt/my-drive/downloads

- This will create downloads directory on your external drive folder if you don't already have it. You should download installation files into this folder.

On your PC open browser
Go to :
- Linux distribution page https://www.expressvpn.com/setup#linux
- Or latest downloads page : https://www.expressvpn.com/latest#linux
Select Raspberry Pi OS from dropdown list of distribution
Right-click on Download button > Copy link address
- Should be something like: https://www.expressvpn.works/clients/linux/expressvpn_3.30.0.2-1_armhf.deb

On your server cd into /mnt/my-drive/downloads and run download command

 sudo wget {{download_url}}

- Replace {{download_url}} with the link you have copied

2. Install Express VPN

    sudo dpkg -i {{installation_file_name}}

Confirm expressvpn is installed
```
expressvpn
```
This command should give you overview of expressvpn program

3. Activate ExpressVPN.

    expressvpn activate

This will prompt you to enter your activation code
Go to https://www.expressvpn.com/setup#linux - linux setup page on Express VPN website, and you should see your code there. Copy and paste the code in your command line interface where you were prompted.
NOTE: you will not see characters when you paste the code. Just hit Enter to proceed.
If you haven't selected to opt out of diagnostics, do that now. This will disable sending anonymous diagnostics to expressvpn
```
 expressvpn preferences set send_diagnostics false
```

4. Connect & Disconnect to VPN

Ref: https://www.expressvpn.com/support/vpn-setup/app-for-raspberry-pi/#connect

Connect

expressvpn connect

or connect to specific country

expressvpn connect Colombia

Check Status
```
expressvpn status
```
Disconnect
```
expressvpn disconnect
```
To see all the commands simply type
```
expressvpn
```

5. Automatically start on logn

Let's say if we wanted to connect expressvpn to Bahamas automatically when user logs into Raspbery Pi. Then do this:

Open ~/.profile file
"~/" stands for /home/{my_username}. For example if user is admin then "~/" will be "/home/admin/"

Paste this at the bottom of the .profile file

#___________ Run commands on login___________

# Start Express VPN on login
expressvpn connect Bahamas

Reboot
```
sudo reboot
```
Check status
```
expressvpn status
```
It should say
```
Connected to Bahamas
```

Appendix

This section is used to explain concepts in more detail. It is not meant for reading from start to finish. It is meant to be used as a reference when you need to understand a particular concept in more detail.

There will be reference links to Appendix sections from other parts of the book.

Command Line Prompt

Command Line Prompt - is a small text inside the command line interface that is printed by the system before every command that you execute. This text informs user of his username, computer name, current folder location, and account type (normal user or root).

The format of the command line prompt is

{{USERNAME}}@{{COMPUTER_NAME}}:{{CURRENT_DIRECTORY_LOCATION_PATH}} {{ACCOUNT_TYPE}}

For example:

john@my-home-server:/home $

Account Type Symbol - is the symbol printed at the end of the Command Line Prompt. It can be $ or #

$ - stands for normal account

# - stands for superuser / root account. # symbol will be visible instead of $ only when you are logged in as a root account

When you first open command line, you are automatically placed inside ~ (tilde) folder - which in fact is your User Home folder.

For example: if we log into computer called my-home-server with a username john, we will see prompt:

john@my-home-server:~ $

In above example "~" is a short notation for "/home/john/"

User Home Directory

User Home Directory - is a directory created automatically by the operating system at the time of user account creation. This directory is intended for storing only user related documents and programs.

The following is the location of user's home directory on the main 3 operating systems:

OS (Operating System)	User's Home location
Linux	/home/{{USERNAME}}
macOS	/Users/{{USERNAME}}
Windows	C:\Users\{{USERNAME}}

NOTE: In Windows operating system we use back slash symbol "\" to separate folders in the file path. In most other operating systems we use forward slash "/".

~ (tilde symbol) - is a shorthand notation for User Home directory path. In Linux command line, User Home directory path can be replaced with tilde symbol ~

You can navigate into User Home directory by using short notation "~" instead of the whole User Home path

cd ~

When inside User Home directory, the command line prompt will display ~ instead of the full directory path. It will look like this:

john@my-home-server:~ $

Dot Directories

Dot Directories - are hidden directories whose names start with a dot symbol. Dot directories are normally used to store configuration data for the application named the same as the dot-directory without a dot.

For example: - Visual Studio Code application data for user John on Windows is stored inside "C:\Users\John\.vscode"

Because the dot directories are hidden, we need to show them to be able to view them:

In Windows 11 : Open File Explorer > View > Show > Hidden items
In Linux and OS X terminal : Add argument "a" to list command (it means show all files and folders including hidden)

ls -a OR

ls -la

Permissions Explained

When we run command ls -l we can see file permissions displayed at the start of each line representing file or folder inside the folder we are currently in.

It looks something like this:

    drwxr-xr-x 5 admin developers 4096 Apr 10 02:21 repos

Symbolic notation

Ten characters that represent symbolic notation of file or folder permisisons are: drwxrwxrwx

The first character, d, signifies that the file is a directory. It can be blank (-) or one of the following characters:

d: directory
c: Character device
b: Block device
s: socket
p: pipe
D: Door
l: symbolic link etc.

Owner - Next three characters (drwxr-xr-x), are permissions for the owner of the file/folder
Group - Next three characters (drwxr-xr-x), permissions for the group
Others - Last three characters (drwxr-xr-x), permissions for all the other users

Meaning of each character is as follows:

    - : Empty - no permission
    r : Read
    w : Write
    x : Execute

Numeric notation

Permisisons can be displayed in numeric notation. Numerals used are the following:

0 : No permission
1 : Execute (x)
2 : Write (w)
4 : Read (r)

The numbers are added together to form one digit number that represents combination of rwx for either an owner, group or other. For example :

Numeric	Symbolic
7	rwx
6	rw-
3	-wx

So the permission rwxrwxrwx is same as 777, rwxr-xr-x is same as 755, and so on.

FSTAB File Syntax

In this section we just layout the full syntax of fstab entry.

FSTAB ENTRY

Example line in /etc/fstab file (aka fstab entry):

 UUID=aa60d5a8-6a7f-43f6-8c41-8958ae018526 /mnt/my-drive ext4 defaults,auto,users,rw,nofail 0 0

Structure:

{{DEVICE}} {{MOUNT_POINT}} {{FILE_SYSTEM_TYPE}} {{OPTIONS}} {{DUMP}} {{PASS}}

Fields Explained:

Field	Description
DEVICE	/dev location or UUID of the device/partition
MOUNT_POINT	The file path location where the device will be mounted.
FILE_SYSTEM_TYPE	The type of file system on the device.
OPTIONS	Mount options, separated by commas. See FSTAB Options Section for the list of options and their meaning.
DUMP	Can be 0 or 1. Enable or disable backing up of the device/partition (the command dump). 0 means no backup. 1 means backup.
PASS	Can be 0, 1 or 2. Controls the order in which fsck checks the device/partition for errors at boot time. The root device should be 1. Other partitions should be 2, or 0 to disable checking.

FSTAB OPTIONS

NOTE: options with slashes mean that you can choose only one of the options separated by slash, for example: auto/noauto - means that you can write either auto or noauto but not both.

Option	Description
auto/noauto	partition is mounted automatically on boot (or not)
ro/rw	“ro” is read-only, and “rw” is read-write. If you want to be able to write to a file-system as the user and not as root, you’ll need to have “rw” specified.
exec/noexec	partition can execute binaries (or not). Usually set to “noexec” for security
nouser/user/users	Using user or users defaults to noexec for all user accounts. So if you need to execute binaries and still mount as a user, be sure to explicitly use “exec” as an option.
nouser	only root can mount the filesystem
user	any user can mount the filesystem. Only the user that mounted a filesystem can unmount it again
users	any user can mount or unmount the filesystem
nofail	the system will look for your disk (and partition) at boot time. If the device is plugged, the filesystem will be mounted. If not, the boot will continue as normal.
sync/async	“sync” forces writing to occur immediately on execution of the command, which is ideal for floppies and USB drives, but isn’t entirely necessary for internal hard disks. What “async” does is allow the command to execute over an elapsed time period, perhaps when user activity dies down and the like. Ever get a message asking to your “wait while changes are being written to the drive?” This is usually why.

These options are separated by a comma and no spaces, and can be put in any order.

Format Device in Desktop UI

For Desktop formatting, you need to have a monitor and keyboard connected to your server machine. Or you can RDP into it from Windows computer.

Depending on your server's operating system, you will need to use different programs to format the external drive.

We describe below how to format the drive in Linux Mint and Raspberry Pi desktop.

Linux Mint - Format on Desktop

In Linux Mint formating external drive is very easy.

Right click on the drive icon and select Format, if that option is available

If you can't see option Format on the context menu, you need to open program USB Stick Formatter

Click on Start icon (LM) in the bottom left corner of the screen. This will open the main menu and you will see the list of programs.
Start typing format and you should see USB Stick Formatter program
Click on it to open it.
You will see 3 fields: USB stick, Filesystem, Volume label. Make sure to:
select the correct USB stick - You can mouse over the USB stick icon, in the left file explorer panel, to see the name of the USB stick. For example: /dev/sda1
select EXT4 as Filesystem
type in a name for Volume label.For example:

USB stick /dev/sda1

Filesystem EXT4

Volume label my-drive
Click Format
Wait for the formatting to finish. You will see a confirmation message when it's done.
Open file explorer
You should see your external drive mounted on the left panel under Devices section
Click on it to select it
You should see a folder called lost+found inside it
Right click > Properties on the drive to see the details. Note the location. It should say /media/{{USERNAME}} For example: /media/admin

By default, Linux mounts external drives onto /media/{{USERNAME}} folder.

We will learn later how to mount the drive onto a different folder.

Raspberry Pi - Format on Desktop

In Raspberry Pi we use program Gparted to format the external drive.

Click on Main Menu - Start icon (Raspberry) in the top left corner of the screen. This will open the main menu and you will see the list of programs.
You should see menu item System Tools > GParted. If you don't see it, you need to install it first.

To install GParted:

Click on Main Menu > Preferences > Add/Remove Software
Type gparted in the search bar and hit Enter
You should see 2 packages: GNOME partition editor and GNOME partition editor - common data
Check the boxes next to both packages and click Apply at the bottom right of the window
Wait for the installation to finish

You should be able to see GParted in the main menu now

Click on Main Menu > System Tools > GParted to open it
Select your external drive from the drop down menu in the top right corner of the window. It should be something like /dev/sda1
You will see a list of partitions with only one partition named like /dev/sda1
Righ-click on the partition and select Format to > ext4
Click on Green tick icon at the top of the window to apply the changes

You will see a confirmation message when formating is completed.

Reboot
Open file explorer
You should see your external drive mounted on the left panel inside folder /media/{{USERNAME}}. For example: "/media/admin/2.1 TB Volume"

By default, Linux mounts external drives onto /media/{{USERNAME}} folder.

We will learn later how to mount the drive onto a different folder.


Client Machine Name	my-pc
Operating System	Windows
Username	Admin
User directory	C:\Users\Admin\


Server Machine Name (hostname)	my-home-server
Operating System	Raspberry Pi OS
Username	admin
User directory	/home/admin/


device name	/dev/sda1
device id	UUID="5C24-1453"
device type	TYPE="exfat"


UUID	5C24-1453
TYPE	exfat
MOUNT_DIR_PATH	/mnt/my-drive


USB stick	/dev/sda1
Filesystem	EXT4
Volume label	my-drive