Book Image

OpenVPN Cookbook - Second Edition

By : Jan Just Keijser
Book Image

OpenVPN Cookbook - Second Edition

By: Jan Just Keijser

Overview of this book

OpenVPN provides an extensible VPN framework that has been designed to ease site-specific customization, such as providing the capability to distribute a customized installation package to clients, and supporting alternative authentication methods via OpenVPN’s plugin module interface. This book provides you with many different recipes to help you set up, monitor, and troubleshoot an OpenVPN network. You will learn to configure a scalable, load-balanced VPN server farm that can handle thousands of dynamic connections from incoming VPN clients. You will also get to grips with the encryption, authentication, security, extensibility, and certifications features of OpenSSL. You will also get an understanding of IPv6 support and will get a demonstration of how to establish a connection via IPv64. This book will explore all the advanced features of OpenVPN and even some undocumented options, covering all the common network setups such as point-to-point networks and multi-client TUN-style and TAP-style networks. Finally, you will learn to manage, secure, and troubleshoot your virtual private networks using OpenVPN 2.4.
Table of Contents (17 chapters)
OpenVPN Cookbook - Second Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Windows - updating the DNS cache


A frequently recurring question on the OpenVPN users mailing lists is related to the DNS name resolution on Windows after the VPN connection is established. If the OpenVPN server pushes out a new DNS server, then this is automatically picked up by the OpenVPN client, yet the name resolution does not always work right after establishing the connection. This has little to do with OpenVPN and more to do with the way the Windows DNS caching service works. As this question comes up quite regularly, a new directive, register-dns, was added in OpenVPN 2.1.3. When this directive is specified, OpenVPN updates the Windows DNS cache and registers the VPN IP address in the Windows DNS tables. As this feature was introduced only recently, this recipe will also show how the Windows DNS cache can be updated using a script when the VPN connection is established. Some users disable the DNS caching service altogether, which seems to have little impact on the operating system...