Troubleshooting Virtual Private Networks (VPN)

Product Description

Master advanced troubleshooting techniques for IPSec, MPLS Layer-3, MPLS Layer-2 (AToM), L2TPv3, L2TPv2, PPTP, and L2F VPNs

• Learn the step-by-step, end-to-end methodology essential for troubleshooting virtual private networks (VPNs)
• Gain the in-depth knowledge necessary for fast and efficient troubleshooting of IPSec, MPLS Layer-3, MPLS Layer-2 (AToM), L2TPv3, L2TPv2, PPTP, and L2F VPNs
• Master advanced troubleshooting tools and techniques for all applicable VPN types
• Debug and fix IPSec site-to-site and remote access VPN issues, such as IKE (ISAKMP) phase 1 and phase 2 negotiation failure, ESP and AH traffic drops, certificate enrollment failures, and maximum transmission unit (MTU) problems
• Locate and resolve MPLS Layer-3 VPN problems, such as those involving route exchange and label switched path (LSP) failure, MPLS VPN over traffic engineering tunnels, and Multicast VPNs (MVPN)
• Discover solutions for issues in AToM and L2TPv3-based Layer-2 VPNs, including pseudowire setup failures, attachment circuit problems, and MTU issues
• Obtain answers for L2TPv2, PPTP, and L2F control connection establishment, session setup, PPP negotiation, and VPN performance issues
• Refer to specially designed flowcharts to identify issues and find solutions fast
• Consolidate VPN troubleshooting knowledge through bonus hands-on labs
• Read and understand detailed analysis of all relevant VPN show and debug command output

Troubleshooting Virtual Private Networks presents a systematic troubleshooting methodology for network engineers, administrators, and architects tasked with managing and deploying Cisco IOS VPNs. With eight self-contained chapters designed to facilitate rapid and straightforward troubleshooting, this book provides detailed information on addressing all common and not-so-common issues with IPSec VPNs, MPLS Layer-3 VPNs, Any Transport over MPLS (AToM)-based Layer-2 VPNs, L2TP Version 3 (L2TPv3)-based Layer-2 VPNs, L2TP Version 2 (L2TPv2) VPNs, PPTP VPNs, and L2F VPNs. This book not only shows you how to correct problems but also how to avoid them in the first place with expert VPN configuration guidance and optimization tips.

Each chapter in Troubleshooting Virtual Private Networks includes a step-by-step, end-to-end troubleshooting approach to a different VPN technology. In-depth technical discussions and configuration reviews orient you to the VPN technology and get you ready to work. To help you access the answers you need, you'll find flowcharts in each chapter that provide a roadmap for rapid issue resolution. Solutions to complex or unusual issues can be found in case studies at the end of each chapter, along with review questions that test your knowledge. Bonus troubleshooting labs are also included to help you consolidate the skills learned throughout the book.

Whether you are looking to update or hone your skills, Troubleshooting Virtual Private Networks is your first and last reference for mastering advanced VPN troubleshooting.

This book is part of the Networking Technology Series from Cisco Press¿ which offers networking professionals valuable information for constructing efficient networks, understanding new technologies, and building successful careers.

Downloads

Lab configurations prepared by the author to be used in conjunction with the book
Download - 58.4 KB - TroubleshootingVPNsLabs.zip

Tips

Tips for troubleshooting Virtual Private Networks
Mark Lewis

Virtual private networking technologies are many and varied. There are, however, a number of tips that will aid in the troubleshooting all of these technologies.

Baseline your network
Make sure that you baseline the performance of your network. Collect information and statistics such as utilization, latency, and error rates. This will enable you to quickly recognize any issues that crop up on your network.

Know your VPN technology
Fast and efficient troubleshooting of VPN technologies requires a good knowledge of the technologies themselves. It's too late to acquire this knowledge when things go wrong, so make sure you acquire it in advance!

Adopt a systematic approach
Virtual private network technologies are complex, and therefore require a systematic approach to troubleshooting.

Some VPN technologies such as L2TPv2 require an asymmetrical approach to troubleshooting. In this case, you should begin on the tunnel-initiating device, and methodically troubleshoot tunnel setup to the tunnel-terminating device.

Other VPN technologies such as MPLS require a symmetrical approach to troubleshooting. In this case, you should begin troubleshooting on the ingress provider edge (PE) router (or attached customer edge (CE) router), and methodically troubleshoot to the egress PE router (or connected CE router). You should then begin troubleshooting in the opposite direction.

Understand your troubleshooting tools
Ensure you have a good understanding of the troubleshooting tools available to you.

If you are troubleshooting MPLS VPNs, you'll need to familiarise yourself with the output of the show ip cef, show mpls, and show ip bgp vpnv4 vrf commands, for example.

Make sure you also understand the impact of debug commands on the network device, as well as methods of alleviating their effect. For example, you should consider using the debug condition command to limit the output of certain debug commands.

Customer Reviews

6 of 6 people found the following review helpful Great Service Provider VPN resource, March 9, 2005 By  Paul Miller "Network Planner" (Portland, OR) - See all my reviews    This review is from: Troubleshooting Virtual Private Networks (VPN) (Hardcover) I recently read the book titled "Troubleshooting Virtual Private Networks" by Mark Lewis. ISBN: 1587051044. This title covers Virtual Private Networking of many flavors. The term Virtual Private Network is a term used very loosely in the industry, so it's good to clarify the 'type' of VPN that's covered in this book. The type of VPN's covered in this books are essentially network based VPNs. The reason I mention this is because some folks call a software utility named SSH a form of VPN. Others stretch the term and call the use of HTTP over Secure Socket Layer (SSL) a VPN. To me the network layer VPN is the only true VPN and are the type covered in this title. The book covers all the major protocols used to accomplish VPNs. From the Cisco proprietary Layer 2 Forwarding protocol to Microsoft's Point-to-Point Tunneling Protocol to the more widely deployed IP Security (IPSEC) Protocol. There is a wealth of information cover Layer 2 Tunneling Protocol (L2TP) and its... Read more Help other customers find the most helpful reviews  Was this review helpful to you?  Report abuse | Permalink  Comment 8 of 9 people found the following review helpful Fun with Tunneling, July 4, 2004 By  A. Sardella (Sunnyvale, CA United States) - See all my reviews    This review is from: Troubleshooting Virtual Private Networks (VPN) (Hardcover) Troubleshooting VPNs by Mark Lewis (Cisco Press, 2004) demystifies the major protocols used to create Virtual Private Networks. VPNs use a form of encapsulation called tunneling, or additions to packets or frames to make them distinguishable as part of a unique connection, to transmit different protocols or encrypted data across the wide area network. The cost savings over dedicated leased line access-extended connectivity with potentially more bandwidth for less money-were compelling from the start, and the standardization process to secure VPNs and make them easier to implement moved quickly. But VPNs also meant that many disparate protocols (PAP/CHAP, LCP/NCP, ATM, IP) with many different functions (authentication, negotiation, and transport) would have to play together in new ways. The inevitable free-for-all that results from these "forced parties" has opened up a world of opportunity for network engineers with troubleshooting skills. That's where this book comes in to help... Read more Help other customers find the most helpful reviews  Was this review helpful to you?  Report abuse | Permalink  Comment 3 of 4 people found the following review helpful Specifically intended for the use of network engineers, October 10, 2004 By  Midwest Book Review (Oregon, WI USA) - See all my reviews This review is from: Troubleshooting Virtual Private Networks (VPN) (Hardcover) Troubleshooting Virtual Private Networks presents by computer hardware and software expert Mark Lewise is a 1000 page systematic troubleshooting methodology "how to" manual specifically intended for the use of network engineers, administrators, and architects tasked with managing and deploying Cisco IOS VPNs. With eight self-contained chapters organized and designed to facilitate rapid and straightforward troubleshooting, Troubleshooting Virtual Private Networks provides detailed information on addressing all common and not-so-common issues associated with IPSec VPNs, MPLS Layer-3 VPNs, any transport over MPLS (AToM)-based Layer-2 VPNs, L2TP Version 3 (L2TPv3)-based Layer-2 VPNs, L2TP Version 2 (L2TPv2) VPNs, PPTP VPNs, and L2F VPNs. Troubleshooting Virtual Private Networks not only shows the user how to correct problems but also how to avoid them in the first place with expert VPN configuration guidance and optimization tips. Help other customers find the most helpful reviews  Was this review helpful to you?  Report abuse | Permalink  Comment

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Review by Paul Miller, SCE, CNX
Review by Alan Sardella, CCNP

Index

Download - 380 KB -- Index

Table of Contents

Introduction.

Downloadable Sample Chapter

Download - 587 KB -- Excerpt from Chapter 6: Troubleshooting Multiprotocol Label Switching Layer 3 VPNs