Book Image

Troubleshooting OpenVPN

By : Eric F Crist
Book Image

Troubleshooting OpenVPN

By: Eric F Crist

Overview of this book

OpenVPN, the most widely used open source VPN package, allows you to create a secure network across systems, keeping your private data secure. Connectivity and other issues are a pain to deal with, especially if they are impacting your business. This book will help you resolve the issues faced by OpenVPN users and teach the techniques on how to troubleshoot it like a true expert. This book is a one stop solution for troubleshooting any issue related to OpenVPN. We will start by introducing you to troubleshooting techniques such as Packet Sniffing, Log Parsing, and OpenSSL. You will see how to overcome operating system specific errors. Later on, you will get to know about network and routing errors by exploring the concepts of IPv4 and IPv6 networking issues. You will discover how to overcome these issues to improve the performance of your OpenVPN deployment. By the end of the book, you will know the best practices, tips, and tricks to ensure the smooth running of your OpenVPN.
Table of Contents (16 chapters)

File and process permissions


For OpenVPN to be effective, the user running the OpenVPN process will need to have the necessary privileges and access to the system, networking, and filesystem. This includes access to writing log files, modifying network adapter settings and the system routing tables, and executing scripts or programs.

Privilege de-escalation

As stated earlier, to make many of the network and routing changes, OpenVPN will need some initial privileges in excess of a typical user. Once these changes have been made, there is usually no need to retain these administrative rights. Using the --user and --group configuration parameters, the administrator can instruct OpenVPN that unprivileged user to operate as once the initialization process has completed.

There are caveats to dropping to an unprivileged user, however. First, all files that the OpenVPN process needs to use during normal operation must be readable and/or writable by the unprivileged user. This includes --client-config...