book

Ubuntu 20.04 Essentials

by Neil Smyth

August 2020

Beginner

328 pages

8h 21m

English

Packt Publishing

Read now

Unlock full access

1.1 Superuser Conventions1.2 Opening a Terminal Window1.3 Editing Files1.4 Feedback1.5 Errata
2.1 What exactly is Linux?2.2 UNIX Origins2.3 Who Created Linux?2.4 The History of Ubuntu2.5 What does the word “Ubuntu” Mean? 2.6 Summary
3.1 Ubuntu Installation Options3.2 Server vs. Desktop Editions3.3 Obtaining the Ubuntu Installation Media3.4 Writing the ISO Installation Image to a USB Drive3.4.1 Linux3.4.2 macOS3.4.3 Windows3.5 Booting from the Ubuntu USB Image3.6 Installing Ubuntu3.7 Accessing the Ubuntu Desktop3.8 Installing Updates3.9 Displaying Boot Messages3.10 Summary
4.1 Network Installer Advantages4.2 Obtaining the Network Installer Image4.3 Booting from the Installer Image4.4 Performing the Installation4.5 Disk Partitioning4.6 Software Collection Selection4.7 Installing Software Collections After System Setup4.8 Summary
5.1 Beginning the Ubuntu Installation 5.2 Booting Ubuntu for the First Time5.3 Changing the Default Boot Option5.4 Accessing the Windows Partition from the Command-line5.5 Accessing the Windows Partition from the Desktop5.6 Summary
6.1 Unmounting the Windows Partition6.2 Deleting the Windows Partitions from the Disk 6.3 Formatting the Unallocated Disk Partition 6.4 Mounting the New Partition 6.5 Editing the Boot Menu6.6 Using the GNOME Disks Utility6.7 Summary
7.1 Installing the GNOME Desktop7.2 An Overview of the GNOME 3 Desktop7.3 Launching Activities7.4 Managing Windows7.5 Using Workspaces7.6 Calendar and Notifications7.7 Desktop Settings7.8 Customizing the Dash7.9 Switching to Dark Mode7.10 Installing Ubuntu Software7.11 Beyond Basic Customization7.12 Summary
8.1 An Overview of Cockpit8.2 Installing and Enabling Cockpit8.3 Accessing Cockpit8.4 Overview8.5 Logs8.6 Storage8.7 Networking8.8 Accounts8.9 Services8.10 Applications8.11 Virtual Machines8.12 Software Updates8.13 Terminal8.14 Connecting to Multiple Servers8.15 Summary
9.1 What is a Shell?9.2 Gaining Access to the Shell9.3 Entering Commands at the Prompt9.4 Getting Information about a Command9.5 Bash Command-line Editing9.6 Working with the Shell History9.7 Filename Shorthand9.8 Filename and Path Completion9.9 Input and Output Redirection9.10 Working with Pipes in the Bash Shell9.11 Configuring Aliases9.12 Environment Variables9.13 Writing Shell Scripts9.14 Summary
10.1 User Management from the Command-line 10.2 User Management with Cockpit10.3 User Management using the Settings App10.4 Summary

11.1 Understanding Ubuntu systemd Targets11.2 Understanding Ubuntu systemd Services11.3 Ubuntu systemd Target Descriptions11.4 Identifying and Configuring the Default Target11.5 Understanding systemd Units and Unit Types11.6 Dynamically Changing the Current Target11.7 Enabling, Disabling and Masking systemd Units11.8 Working with systemd Units in Cockpit11.9 Summary
12.1 Repositories12.2 Managing Repositories with Software & Updates12.3 Managing Packages with APT12.4 Performing Updates12.5 Enabling Automatic Updates12.6 Enabling Livepatch12.7 Summary
13.1 Managing Software with Snap13.2 Basic Snap Commands13.3 Working with Snap Channels13.4 Snap Refresh Schedule13.5 Snap Services13.6 Summary
14.1 An Introduction to NetworkManager14.2 Installing and Enabling NetworkManager14.3 Basic nmcli Commands14.4 Working with Connection Profiles14.5 Interactive Editing14.6 Configuring NetworkManager Permissions14.7 Summary
15.1 Understanding Ports and Services 15.2 Securing Ports and Services15.3 Ubuntu Services and iptables Rules15.4 Well Known Ports and Services15.5 Summary
16.1 An Overview of gufw and ufw16.2 Installing gufw on Ubuntu 16.3 Running and Enabling gufw16.4 Creating a New Profile16.5 Adding Preconfigured Firewall Rules16.6 Adding Simple Firewall Rules16.7 Adding Advanced Rules16.8 Configuring the Firewall from the Command Line using ufw16.9 Summary
17.1 An Introduction to firewalld17.1.1 Zones17.1.2 Interfaces17.1.3 Services17.1.4 Ports17.2 Checking firewalld Status 17.3 Configuring Firewall Rules with firewall-cmd17.3.1 Identifying and Changing the Default Zone17.3.2 Displaying Zone Information17.3.3 Adding and Removing Zone Services17.3.4 Working with Port-based Rules17.3.5 Creating a New Zone17.3.6 Changing Zone/Interface Assignments17.3.7 Masquerading 17.3.8 Adding ICMP Rules17.3.9 Implementing Port Forwarding17.4 Managing firewalld using firewall-config17.5 Summary
18.1 An Overview of Secure Shell (SSH)18.2 SSH Key-based Authentication18.3 Setting Up Key-based Authentication18.4 Installing and Starting the SSH Service18.5 SSH Key-based Authentication from Linux and macOS Clients18.6 Managing Multiple Keys18.7 SSH Key-based Authentication from Windows 10 Clients18.8 SSH Key-based Authentication using PuTTY18.9 Generating a Private Key with PuTTYgen18.10 Installing the Public Key for a Google Cloud Instance18.11 Summary
19.1 Remote Desktop Access Types19.2 Secure and Insecure Remote Desktop Access19.3 Enabling Remote Desktop Access on Ubuntu19.4 Connecting to the Shared Desktop19.5 Connecting from Non-Linux Clients19.6 Establishing a Secure Remote Desktop Session 19.7 Establishing a Secure Tunnel on Windows using PuTTY19.8 Summary
20.1 Installing the GNOME Desktop Environment20.2 Installing VNC on Ubuntu20.3 Configuring the VNC Server20.4 Starting the VNC Server20.5 Connecting to a VNC Server20.6 Summary
21.1 Requirements for Remotely Displaying Ubuntu Applications 21.2 Remotely Displaying an Ubuntu Application 21.3 Trusted X11 Forwarding 21.4 Compressed X11 Forwarding 21.5 Displaying Remote Ubuntu Apps on Windows21.6 Summary
22.1 Ensuring NFS Services are running on Ubuntu22.2 Configuring the Ubuntu Firewall to Allow NFS Traffic 22.3 Specifying the Folders to be Shared 22.4 Accessing Shared Ubuntu Folders 22.5 Mounting an NFS Filesystem on System Startup 22.6 Unmounting an NFS Mount Point 22.7 Accessing NFS Filesystems in Cockpit22.8 Summary
23.1 Accessing Windows Resources from the GNOME Desktop23.2 Samba and Samba Client23.3 Installing Samba on an Ubuntu System 23.4 Configuring the Ubuntu Firewall to Enable Samba 23.5 Configuring the smb.conf File23.5.1 Configuring the [global] Section23.5.2 Configuring a Shared Resource23.5.3 Removing Unnecessary Shares23.6 Creating a Samba User23.7 Testing the smb.conf File23.8 Starting the Samba and NetBIOS Name Services23.9 Accessing Samba Shares23.10 Accessing Windows Shares from Ubuntu23.11 Summary
24.1 Guest Operating System Virtualization 24.2 Hypervisor Virtualization 24.2.1 Paravirtualization 24.2.2 Full Virtualization24.2.3 Hardware Virtualization 24.3 Virtual Machine Networking24.4 Summary
25.1 An Overview of KVM 25.2 KVM Hardware Requirements25.3 Preparing Ubuntu for KVM Virtualization 25.4 Verifying the KVM Installation25.5 Summary
26.1 Installing the Cockpit Virtual Machines Module26.2 Creating a Virtual Machine in Cockpit26.3 Starting the Installation26.4 Working with Storage Volumes and Storage Pools26.5 Creating a Virtual Machine using virt-manager26.6 Starting the Virtual Machine Manager26.7 Configuring the KVM Virtual System 26.8 Starting the KVM Virtual Machine 26.9 Summary
27.1 Running virt-install to build a KVM Guest System 27.2 An Example Ubuntu virt-install Command 27.3 Starting and Stopping a Virtual Machine from the Command-Line27.4 Creating a Virtual Machine from a Configuration File27.5 Summary
28.1 Identifying the Network Management System28.2 Getting the Netplan Network Settings28.3 Creating a Netplan Network Bridge28.4 Getting the Current Network Manager Settings28.5 Creating a Network Manager Bridge from the Command-Line28.6 Declaring the KVM Bridged Network28.7 Using a Bridge Network in a Virtual Machine28.8 Creating a Bridge Network using nm-connection-editor28.9 Summary
29.1 The virsh Shell and Command-Line29.2 Listing Guest System Status 29.3 Starting a Guest System 29.4 Shutting Down a Guest System 29.5 Suspending and Resuming a Guest System 29.6 Saving and Restoring Guest Systems 29.7 Rebooting a Guest System 29.8 Configuring the Memory Assigned to a Guest OS 29.9 Summary
30.1 Linux Containers and Kernel Sharing30.2 Container Uses and Advantages30.3 Ubuntu Container Tools30.4 The Docker Registry30.5 Container Networking30.6 Summary
31.1 Installing the Container Tools31.2 Pulling a Container Image31.3 Running the Image in a Container31.4 Managing a Container31.5 Saving a Container to an Image31.6 Removing an Image from Local Storage31.7 Removing Containers31.8 Building a Container with Buildah31.9 Summary
32.1 Requirements for Configuring an Ubuntu Web Server 32.2 Installing the Apache Web Server Packages32.3 Configuring the Firewall32.4 Port Forwarding 32.5 Starting the Apache Web Server 32.6 Testing the Web Server 32.7 Configuring the Apache Web Server for Your Domain 32.8 The Basics of a Secure Web Site32.9 Configuring Apache for HTTPS32.10 Obtaining an SSL Certificate32.11 Summary
33.1 The structure of the Email System 33.1.1 Mail User Agent 33.1.2 Mail Transfer Agent 33.1.3 Mail Delivery Agent 33.1.4 SMTP 33.1.5 SMTP Relay33.2 Configuring an Ubuntu Email Server 33.3 Postfix Pre-Installation Steps 33.4 Firewall/Router Configuration33.5 Installing Postfix on Ubuntu33.6 Configuring Postfix 33.7 Configuring DNS MX Records33.8 Starting Postfix on an Ubuntu System33.9 Testing Postfix33.10 Sending Mail via an SMTP Relay Server33.11 Summary
34.1 Mounted File Systems or Logical Volumes 34.2 Finding the New Hard Drive 34.3 Creating Linux Partitions 34.4 Creating a File System on a Disk Partition 34.5 An Overview of Journaled File Systems34.6 Mounting a File System 34.7 Configuring Ubuntu to Automatically Mount a File System 34.8 Adding a Disk Using Cockpit34.9 Summary
35.1 An Overview of Logical Volume Management (LVM) 35.1.1 Volume Group (VG)35.1.2 Physical Volume (PV) 35.1.3 Logical Volume (LV) 35.1.4 Physical Extent (PE) 35.1.5 Logical Extent (LE) 35.2 Getting Information about Logical Volumes 35.3 Adding Additional Space to a Volume Group from the Command-Line 35.4 Summary
36.1 What is Swap Space?36.2 Recommended Swap Space for Ubuntu36.3 Identifying Current Swap Space Usage36.4 Adding a Swap File to an Ubuntu System36.5 Adding Swap as a Partition36.6 Adding Space to an Ubuntu LVM Swap Volume36.7 Adding Swap Space to the Volume Group36.8 Summary
37.1 Managing Processes37.2 Real-time System Monitoring with htop37.3 Command-Line Disk and Swap Space Monitoring37.4 Summary

Content preview from Ubuntu 20.04 Essentials

15. Ubuntu Firewall Basics

A firewall is a vital component in protecting an individual computer system or network of computers from external attack (typically from an internet connection). Any computer connected directly to an internet connection should ideally run a firewall to protect against malicious activity. Similarly, any internal network must have some form of firewall between it and an external internet connection.

Ubuntu is supplied with powerful firewall technology known as iptables built-in. Entire books can, and indeed have, been written about configuring iptables. If you would like to learn about iptables we recommend:

https://www.linuxtopia.org/Linux_Firewall_iptables/index.html

The goal of this chapter is to cover some of the ...