Chapter21.Remote Access VPN Troubleshooting

Chapter 21. Remote Access VPN Troubleshooting

Virtual Private Network (VPN) is private networking over public networks. In the troubleshooting context, this implies different narrowband and broadband technologies as Internet access alternatives. The technologies discussed in Part II, "Dial," Part III, "ISDN," and Part IV, "Frame Relay," are not known to pose any restrictions over VPN. If they do, it is not technology-related, but a VPN-related issue, and all the principles of VPN troubleshooting apply. For this reason, more detailed information is provided in this chapter for technologies that require specific knowledge and adjustments when used with VPN. The emphasis is on the client side because the client issues and problems supercede all others combined. To facilitate troubleshooting, the entire VPN implementation chain is divided into three areas:

• Troubleshooting of Cisco remote access VPN clients, which includes the following:

  - Cisco VPN Unity software client troubleshooting

  - Cisco 3002 HW client troubleshooting

  - Cisco Easy VPN client troubleshooting

  - Cisco PIX hardware client troubleshooting

• Internet technologies and remote access VPNs sections include VPN-related troubleshooting information for the following technologies:

  - VPN and asymmetric DSL (ADSL)

  - VPN over cable

  - VPN over wireless and satellite

• Local-area networks (LANs) and remote access VPNs sections are focused on common networking issues that affect VPN connections.

The information in this chapter allows you to show and debug some VPN events. Additionally, the VPN clients and the VPN concentrator allow you to review post-factum large log files for troubleshooting purposes. Some of the outputs are provided in this chapter because of their importance, despite their large size. It is important to review your performance criteria before approaching VPN troubleshooting.