Book Image

Ubuntu 20.04 Essentials

By : Neil Smyth
Book Image

Ubuntu 20.04 Essentials

By: Neil Smyth

Overview of this book

Ubuntu is undeniably one of the most highly regarded and widely used Debian-based Linux distributions available today. Thanks to its ease of use and reliability, Ubuntu has a loyal following of Linux users and an active community of developers. Ubuntu 20.04 Essentials is designed to take you through the installation, use, and administration of the Ubuntu 20.04 distribution in detail. For beginners, the book covers topics such as operating system installation, the basics of the GNOME desktop environment, configuring email and web servers, and installing packages and system updates. Additional installation topics such as dual booting with Microsoft Windows are also covered along with crucial security topics such as configuring a firewall and user and group administration. For the experienced user, the book delves into topics such as remote desktop access, the Cockpit web interface, logical volume management (LVM), disk partitioning, and swap management. Further, it also explores KVM virtualization, Secure Shell (SSH), Linux containers, and file sharing using both Samba and NFS to provide a thorough overview of this enterprise-class operating system.
Table of Contents (38 chapters)
38
Index

16.7 Adding Advanced Rules

So far we have looked at rules to control only the type of traffic to block (incoming traffic on port 22 for example) regardless of the source or destination of the traffic. It is often the case, however, that rules will need to be defined to allow or deny traffic based on an IP address or range of IP addresses.

For the purposes of an example, assume that the local system has an IP address of 192.168.0.102. The firewall may be configured to only allow access on port 22 from a system with the IP address of, for example, 192.168.0.105. To achieve this, the From: field of the Advanced settings panel should be set to the IP address of the system from which the connection request is originating (in this case 192.168.0.105).

The To: fields provide the option to specify the IP address and port of the system to which the connection is being made. In this example this would be port 22 on the local system (192.168.0.102). The To: IP address is actually optional...