7 Create a Linux Server

The Linux operating system has been increasing in popularity for many reasons. Most Linux platforms are free and open-source with very active development communities. Linux is also very reliable in that it often does not require reboots when something goes wrong. Furthermore, Linux is very customizable so only the features that are required are installed. A bare-bones Linux distribution can run on as little as 58MB of RAM! Finally, most applications on Linux are free and open-source.

Many people are reluctant to use Linux because it generally uses a command line interface (CLI) instead of a graphical user interface (GUI) like Windows or Apple. However, all those easy-to-use images require a lot of RAM and CPU power, so using CLI allows the operating system to focus on the essentials. We use Linux in the GNS3 environment because it requires very little in the way of hardware resources. This allows us to build complex enterprise networks without overloading our hosting machine. This lab will help you download, install, and configure a Ubuntu Linux Server for use in a GNS3 environment.

Learning Objectives

• Successfully download, install, and run Ubuntu Server in a GNS3 environment
• Optional installs for later labs
  • • Phase II – DHCP Server – KIA
    • Phase III – DHCP Server – isc-dhcp-server
    • Phase IV – DNS Server – BIND9
    • Phase V – Text-Based Web Browser – w3m
    • Phase VI – GUI – Ubuntu Desktop
    • Phase VII – Web Hosting Service – Apache2

Prerequisites

• Chapter 2 – Setting up a GNS3 environment
• Chapter 6 – Adding a VM to GNS3

Deliverables

• None – this is a preparatory lab that supports other labs in this book

Resources

• Download Ubuntu Server https://ubuntu.com/download/server

Contributors and Testers

• Quinton D. Heath Van Horn, 7th Grade
• David Reese, Mathematics Student, SUNY Brockport
• Cody Shinkyu Park, Honeywell Software Engineer, ERAU-Prescott Alumni
• Evan Paddock, Cybersecurity Student, ERAU-Prescott
• Dante Rocca, Cybersecurity Student, ERAU-Prescott
• Sawyer Hansen, Cybersecurity Student, ERAU-Prescott

1. Download Ubuntu Server from https://ubuntu.com/download/server
2. Start Oracle Virtual Box Manager
3. Click on New (Figure 1)
   1. Pick a name, for this example, we use something clever like “Ubuntu Server”
   2. Use the dropdown menu to select the Ubuntu Server ISO that you downloaded
   3. Click Skip Unattended Installation IMPORTANT!
   4. Click Next
   5. You can leave the hardware on its defaults –> click next (Figure 2)

      NOTE: If you are planning on installing the GUI interface you will need at least 50GB of hard disk storage in the next step.

   6. Leave the default Virtual Hard Disk settings –> click next (Figure 3)
   7. Review the summary and click on Finish
4. Start the Ubuntu Server VM
5. Use the arrow keys to Install Ubuntu Server (Figure 4)
6. Use the arrow keys to select your language (Figure 5) and your keyboard
7. Use the arrow keys to select Ubuntu Server and press done (Figure 6)
8. Accept the default network connections and select Done (Figure 7)
9. Enter a proxy address if you need one select Done (Figure 8)
10. Enter an alternative Mirror if you know you have one, otherwise, just select Done (Figure 9)
11. Use the default storage configurations and select Done for both screens (Figure 10)
12. Confirm the action and select Continue (Figure 11)
    1. For the profile information, the following is recommended (Figure 12)
       Your Name: student
       Your Servers Name: ubuntu_server
       Pick a username: student
       Chose a password: Security1
13. There is no need to update to Ubuntu Pro, so skip it for now (Figure 13) and continue
14. Select Install OpenSSH Server and continue (Figure 14)
15. No snaps are needed – select done (Figure 15)
16. Allow the installation and update to complete, then select Reboot Now (Figure 16)
17. You might have to hit enter a couple of times depending on the way your VirtualBox is configured
18. Login using the credentials you created earlier

    NOTE: If you are new to Linux, you should know that the password cursor does not move. This is a security feature to mask how many characters the password is. Anyone shoulder surfing can accelerate their password brute force efforts by knowing the length of the password.

1. At the terminal prompt, type

   sudo apt install kea

2. Kea can be configured by typing

   sudo vi /etc/kea/kea-dhcp4.conf

3. The instructions to configure Kea are included in the file
4. You can also use this guide to configure Kea
5. Use this guide to add the Ubuntu Server to the GNS3 Working Environment

1. To install type

   sudo apt install isc-dhcp-server

2. Some shortcut commands for future reference include:
   1. To bind the DHCP server to an interface type

      vi /etc/default/isc-dhcp-server

   2. To configure type

      sudo vi /etc/dhcp/dhcpd.conf

   3. To test the configuration file type

      dhcpd -t

   4. To start the DHCP server type

      sudo systemctl start isc-dhcp-server.service

   5. To enable the DHCP service to start on boot type

      sudo systemctl enable isc-dhcp-server.service

   6. To restart the DHCP server type

      sudo systemctl restart isc-dhcp-server.service

   7. To check the status of the DHCP server type

      sudo systemctl status isc-dhcp-server.service

1. Install software and additional utilities

   sudo apt install -y bind9 dnsutils bind9-utils

2. Modify configurations file

   sudo nano /etc/bind/named.conf.options

3. Configure master zone declarations

   sudo nano /etc/bind/named.conf.local

4. Start DNS daemon

   sudo systemctl start named

5. To restart

   sudo systemctl restart named

6. To check status
   sudo systemctl status named

1.  Install by typing

   sudo apt install w3m

2. Run by typing

   w3m -v http://www.google.com

3. Exit the browser by pressing Ctrl-z

1. To install the GUI type

   sudo apt install ubuntu-desktop

2. Install the display manager by typing

   sudo apt install lightdm

3. Enable the LightDM service by typing

   sudo systemctl start lightdm.service

4. To make sure it starts on boot type

   sudo service lightdm start

5. You may have to restart the Ubuntu VM

   sudo shutdown now -r

1. Install a GUI on the Ubuntu Server by following the steps in Phase 6
2. Install Apache HTTP Server
   1. Install Apache by typing

      sudo apt install apache2

   2. Restart the Apache Server by typing

      sudo service apache2 restart

   3. Test that it is running by opening Firefox and typing 127.0.0.1 in the address bar
   4. Check that it says it works (Figure 17)
3. Install MySQL database management system
   1. From a terminal install mySQL by typing

      sudo apt install mysql-server

   2. Verify it was installed by typing

      sudo mysql -v

   3. Set the password validation by typing

      sudo mysql_secure_installation

      1. Press y and set the password strength according to your needs
      2. Press y to remove anonymous users
      3. Press y to disallow remote root login
      4. Keep the test database by pressing n
      5. Reload the privilege tables by pressing y
   4. Test the operability of mysql
      1. Start mysql by typing

         sudo mysql -u root

      2. Create a database by typing

         create database <name>;

      3. List all the databases by typing

         show databases;

   5. You should have a screen that looks like (Figure 18)
   6. To leave mysql and return back to the Ubuntu Server console, type

      exit

4. Install PHP web-server scripting language module
   1. From the terminal, install PHP by typing

      sudo apt install php

   2. View the version by typing

      php -v

   3. Make a check file by typing

      sudo vi /var/www/html/info.php

      1. Type i and add the following information

         <?php
         phpinfo();
         ?>

      2. Save the file by pressing the escape key followed by

         :wq

   4. Restart the Apache service by typing

      sudo service apache2 restart

   5. Test PHP by opening Firefox and typing the following into the web browser address bar 127.0.0.1/info.php
   6. You should get the following screen (Figure 19)

End of Lab

Figures for Print Version