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)

Common log messages


Understanding the most common log messages present at --verb 4 allows you to quickly scan the log file for errors while also comprehending the events taking place. The messages described here are a mix of both affirmative (good) messages, as well as the most common messages indicating errors.

Startup messages

OpenVPN will evoke a number of messages upon startup. Some of these messages are informational, others are warnings of perhaps new options, or options that are potentially dangerous if used or omitted.

Version and compile string

The first line to explore is the OpenVPN version string. This string will indicate the actual release of the software used along with some important build and compile-time information. The first two examples show OpenVPN version 2.3.11 compiled with OpenSSL, LZO, PKCS11, MH (extended IP packet information), and IPv6.

The second piece of the string lists the processor platform and additional data about the system that performed the compile. Our...