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Cisco Anyconnect L2tp



The network topology for this reference implementation consists of a Cisco VPN 3000 concentrator sitting between two Class-C networks: 10.1.1.xxx/24 on the public interface and 10.2.2.x on the private interface. Details of the reference network can be found in Appendix A – CISCO. In JellyVPN we provide many VPN ports for iPhone & iPad Devices, you can use our VPN from iOS 10 and later, JellyVPN will support many protocols such as Cisco AnyConnect VPN, OpenVPN, IKEv2 VPN, Cisco IPSec VPN, L2TP VPN, PPTP VPN, All VPN servers secured with Valid SSL Security, dedicated with 1Gpbs port. You can download all of them, and using in your iPhjone & iPad with guide & latest. Nov 17, 2016 The problem with the AnyConnect client is that it's not the IPsec client. It doesn't give you the ability to restrict it's execution from a source. Well, not without buying a ton of extra Cisco software to do it. I mean, my case is very specific on this, so AnyConnect is not a valid solution.

Contents

Introduction

Layer 2 tunneling protocols, such as L2TP, do not provide encryption mechanisms for the traffic it tunnels. Instead, they rely on other security protocols, such as IPSec, to encrypt their data. Use this sample configuration to encrypt L2TP traffic using IPSec for users who dial in.

L2TP tunnel is established between the L2TP Access Concentrator (LAC) and the L2TP Network Server (LNS). An IPSec tunnel is also established between these devices and all L2TP tunnel traffic is encrypted using IPSec.

Prerequisites

Requirements

This document requires a basic understanding of IPSec protocol. To learn more about IPSec, please refer to An Introduction to IP Security (IPSec) Encryption.

Components Used

The information in this document is based on these software and hardware versions.

  • Cisco IOS® Software Release 12.2(24a)

  • Cisco 2500 Series Routers

The information presented in this document was created from devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If you are working in a live network, ensure that you understand the potential impact of any command before using it.

Conventions

For more information on document conventions, see the Cisco Technical Tips Conventions.

Configure

In this section, you are presented with the information to configure the features described in this document.

Note: To find additional information on the commands used in this document, use the Command Lookup Tool (registered customers only) .

Network Diagram

This document uses the network setup shown in this diagram. The dial up user initiates a PPP session with the LAC over the analog telephone system. After the user is authenticated, the LAC initiates an L2TP tunnel to the LNS. The tunnel end points, LAC and LNS, authenticate each other before the tunnel is created. Once the tunnel is established, an L2TP session is created for the dialup user. To encrypt all the L2TP traffic between the LAC and LNS, the L2TP traffic is defined as the interesting traffic (traffic to be encrypted) for IPSec.

Configurations

This document uses these configurations.

LAC Configuration
LNS Configuration

Verify

This section provides information you can use to confirm your configuration is working properly.

Certain show commands are supported by the Output Interpreter Tool (registered customers only) , which allows you to view an analysis of show command output.

Use these show commands to verify the configuration.

  • show crypto isakmp sa— Displays all current IKE security associations (SAs) at a peer.

L2tp Cisco Router

  • show crypto ipsec sa—Displays the settings used by current SAs.

  • show vpdn—Displays the information about the active L2TP tunnel.

Troubleshoot

IPsec Negotiation/IKE Protocol Support Page

This section provides information you can use to troubleshoot your configuration.

Troubleshooting Commands

Certain show commands are supported by the Output Interpreter Tool (registered customers only) , which allows you to view an analysis of show command output.

Note: Before issuing debug commands, please see Important Information on Debug Commands.

  • debug crypto engine—Displays engine events.

  • debug crypto ipsec—Displays IPSec events.

  • debug crypto isakmp—Displays messages about IKE events.

  • debug ppp authentication—Displays authentication protocol messages, including CHAP packet exchanges and Password Authentication Protocol (PAP) exchanges.

  • debug vpdn event—Displays messages about events that are part of normal tunnel establishment or shutdown.

  • debug vpdn error—Displays errors that prevent a tunnel from being established or errors that cause an established tunnel to be closed.

  • debug ppp negotiation—Displays PPP packets transmitted during PPP startup, where PPP options are negotiated.

Cisco Anyconnect L2tp

IPSEC

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