ASA/PIX: Static IP Addressing for IPSec VPN Client with CLI and ASDM Configuration Example

Introduction

This document describes how to configure the Cisco 5500 Series Adaptive Security Appliance (ASA) to provide the Static IP address to the VPN client with the Adaptive Security Device Manager (ASDM) or CLI. The ASDM delivers world-class security management and monitoring through an intuitive, easy-to-use Web-based management interface. Once the Cisco ASA configuration is complete, it can be verified with the Cisco VPN Client.

Refer to PIX/ASA 7.x and Cisco VPN Client 4.x with Windows 2003 IAS RADIUS (Against Active Directory) Authentication Configuration Example in order to set up the remote access VPN connection between a Cisco VPN Client (4.x for Windows) and the PIX 500 Series Security Appliance 7.x. The remote VPN Client user authenticates against the Active Directory with a Microsoft Windows 2003 Internet Authentication Service (IAS) RADIUS server.

Refer to PIX/ASA 7.x and Cisco VPN Client 4.x for Cisco Secure ACS Authentication Configuration Example in order to set up a remote access VPN connection between a Cisco VPN Client (4.x for Windows) and the PIX 500 Series Security Appliance 7.x with a Cisco Secure Access Control Server (ACS version 3.2) for extended authentication (Xauth).

Prerequisites

Requirements

This document assumes that the ASA is fully operational and configured to allow the Cisco ASDM or CLI to make configuration changes.

Note: Refer to Allowing HTTPS Access for ASDM or PIX/ASA 7.x: SSH on the Inside and Outside Interface Configuration Example to allow the device to be remotely configured by the ASDM or Secure Shell (SSH).

Components Used

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

• Cisco Adaptive Security Appliance Software Version 7.x and later

• Adaptive Security Device Manager Version 5.x and later

• Cisco VPN Client Version 4.x and later

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Related Products

This configuration can also be used with Cisco PIX Security Appliance Version 7.x and later.

Conventions

Refer to Cisco Technical Tips Conventions for more information on document conventions.

Configure

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

Note: Use the Command Lookup Tool (registered customers only) in order to obtain more information on the commands used in this section.

Network Diagram

This document uses this network setup:

Note: The IP addressing schemes used in this configuration are not legally routable on the Internet. They are RFC 1918 addresses, which were used in a lab environment.

Configure Remote Access VPN (IPSec)

ASDM Procedure

Complete these steps in order to configure the remote access VPN:

1. Choose Configuration > Remote Access VPN > Network (Client) Access > Advanced > IPSec > IKE Policies > Add in order to create a ISAKMP policy.

   

2. Provide the ISAKMP policy details.

   

   Click OK and Apply.

3. Choose Configuration > Remote Access VPN > Network (Client) Access > Advanced > IPSec > IKE Parameters to enable the IKE on the Outside Interface.

   

4. Choose Configuration > Remote Access VPN > Network (Client) Access > Advanced > IPSec > IPSec Transform Sets > Add in order to create the ESP-DES-SHA transform set, as shown.

   

   Click OK and Apply.

5. Choose Configuration > Remote Access VPN > Network (Client) Access > Advanced > IPSec > Crypto Maps > Add in order to create a crypto map with dynamic policy of priority 1, as shown.

   

   Click OK and Apply.

6. Choose Configuration > Remote Access VPN > AAA Setup > Local Users > Add in order to create the user account (for example, username - cisco123 and Password - cisco123) for VPN client access.

   

7. Go to VPN Policy and add the Static/Dedicated IP Address for user "cisco123," as follows.

   

8. Choose Configuration > Remote Access VPN > Network (Client) Access > Address Assignment > Address Pools and click Add to add the VPN Client for VPN Client users.

   

9. Choose Configuration > Remote Access VPN > Network (Client) Access > IPSec Connection Profiles > Add in order to add a tunnel group (for example, TunnelGroup1 and the Preshared key as cisco123), as shown.

   

   • Under the Basic tab, choose the server group as LOCAL for the User Authentication field.

   • Choose vpnclient1 as the Client Address Pools for the VPN Client users.

   

   Click OK.

10. Choose Advanced > Client Addressing and check the Use address pool check box to assign the IP Address to the VPN clients.

    Note: Make sure to uncheck the check boxes for Use authentication server and Use DHCP.

    

    Click OK.

11. Enable the Outside interface for IPSec Access. Click Apply to proceed.

    

Configure the ASA/PIX with CLI

Complete these steps in order to configure the DHCP server to provide IP addresses to the VPN clients from the command line. Refer to Configuring Remote Access VPNs or Cisco ASA 5500 Series Adaptive Security Appliances-Command References for more information on each command that is used.

ASA# sh run
ASA Version 8.0(2)
!

!--- Specify the hostname for the Security Appliance.

hostname ASA
enable password 8Ry2YjIyt7RRXU24 encrypted
names
!


!--- Configure the outside and inside interfaces.

interface Ethernet0/0
 nameif inside
 security-level 100
 ip address 10.1.1.1 255.255.255.0
!
interface Ethernet0/1
 nameif outside
 security-level 0
 ip address 192.168.1.1 255.255.255.0
!
interface Ethernet0/2
 nameif DMZ
 security-level 50
 ip address 192.168.10.2 255.255.255.0


!--- Output is suppressed.


passwd 2KFQnbNIdI.2KYOU encrypted
boot system disk0:/asa802-k8.bin
ftp mode passive

access-list 101 extended permit ip 10.1.1.0 255.255.255.0 
192.168.5.0 255.255.255.0
pager lines 24
logging enable
logging asdm informational
mtu inside 1500
mtu outside 1500
mtu dmz 1500

ip local pool vpnclient1 192.168.5.10-192.168.5.100 mask 255.255.255.0

no failover
icmp unreachable rate-limit 1 burst-size 1


!--- Specify the location of the ASDM image for ASA to fetch the image for ASDM access.

asdm image disk0:/asdm-613.bin
no asdm history enable
arp timeout 14400

global (outside) 1 192.168.1.5
nat (inside) 0 access-list 101
nat (inside) 1 0.0.0.0 0.0.0.0
route outside 0.0.0.0 0.0.0.0 192.168.1.2 1
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 icmp 0:00:02
timeout sunrpc 0:10:00 h323 0:05:00 h225 1:00:00 mgcp 0:05:00 mgcp-pat 0:05:00
timeout sip 0:30:00 sip_media 0:02:00 sip-invite 0:03:00 sip-disconnect 0:02:00
timeout uauth 0:05:00 absolute
dynamic-access-policy-record DfltAccessPolicy
http server enable
http 0.0.0.0 0.0.0.0 inside
no snmp-server location
no snmp-server contact
snmp-server enable traps snmp authentication linkup linkdown coldstart

crypto ipsec transform-set ESP-DES-SHA esp-des esp-sha-hmac
crypto dynamic-map outside_dyn_map 1 set transform-set ESP-DES-SHA
crypto map outside_map 1 ipsec-isakmp dynamic outside_dyn_map


!--- Specifies the interface to be used with !--- the settings defined in this configuration.

crypto map outside_map interface outside


!--- PHASE 1 CONFIGURATION ---! !--- This configuration uses ISAKMP policy 2. !--- The configuration commands here define the Phase !--- 1 policy parameters that are used.

crypto isakmp enable outside

crypto isakmp policy 2
 authentication pre-share
 encryption des
 hash sha
 group 2
 lifetime 86400

no crypto isakmp nat-traversal


!--- Specifies that the IP address to the vpn clients are assigned by the local and not by AAA or dhcp. The CLI vpn-addr-assign local for VPN address assignment through ASA is hidden in the CLI provided by show run command. 

no vpn-addr-assign aaa
no vpn-addr-assign dhcp

telnet timeout 5
ssh timeout 5
console timeout 0
threat-detection basic-threat
threat-detection statistics access-list
!
class-map inspection_default
 match default-inspection-traffic
!
!
policy-map type inspect dns preset_dns_map
 parameters
  message-length maximum 512
policy-map global_policy
 class inspection_default
  inspect dns preset_dns_map
  inspect ftp
  inspect h323 h225
  inspect h323 ras
  inspect netbios
  inspect rsh
  inspect rtsp
  inspect skinny
  inspect esmtp
  inspect sqlnet
  inspect sunrpc
  inspect tftp
  inspect sip
  inspect xdmcp
!
service-policy global_policy global
!
group-policy DfltGrpPolicy attributes
 vpn-tunnel-protocol IPSec webvpn
group-policy GroupPolicy1 internal


!--- In order to identify remote access users to the Security Appliance, !--- you can also configure usernames and passwords on the device. !--- specify the IP address to assign to a particular user, use the vpn-framed-ip-address command !--- in username mode 

username cisco123 password ffIRPGpDSOJh9YLq encrypted
username cisco123 attributes
  vpn-framed-ip-address 192.168.5.1 255.255.255.0

!--- Create a new tunnel group and set the connection !--- type to remote-access.

tunnel-group TunnelGroup1 type remote-access
tunnel-group TunnelGroup1 general-attributes
 address-pool vpnclient1


!--- Enter the pre-shared-key to configure the authentication method.

tunnel-group TunnelGroup1 ipsec-attributes
 pre-shared-key *

prompt hostname context
Cryptochecksum:e0725ca9ccc28af488ded9ee36b7822d
: end
ASA#

Cisco VPN Client Configuration

Attempt to connect to the Cisco ASA with the Cisco VPN Client in order to verify that the ASA is successfully configured.

1. Choose Start > Programs > Cisco Systems VPN Client > VPN Client.

2. Click New to launch the Create New VPN Connection Entry window.

   

3. Fill in the details of your new connection.

   Enter the name of the Connection Entry along with a description. Enter the outside IP address of the ASA in the Host box. Then enter the VPN Tunnel Group name (TunnelGroup1) and password (Pre-shared Key - cisco123) as configured in ASA. Click Save.

   

4. Click the connection that you want to use, and click Connect from the VPN Client main window.

   

5. When prompted, enter the Username : cisco123 and Password : cisco123 as configured in the ASA for Xauth, and click OK to connect to the remote network.

   

6. The VPN Client is connected with the ASA at the central site.

   

7. Once the connection is successfully established, choose Statistics from the Status menu to verify the details of the tunnel.

   

Verify

show Commands

Use this section to confirm that your configuration works properly.

The Output Interpreter Tool (registered customers only) (OIT) supports certain show commands. Use the OIT to view an analysis of show command output.

• show crypto isakmp sa—Shows all current IKE Security Associations (SAs) at a peer.

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

Troubleshoot

This section provides information you can use to troubleshoot your configuration. Sample debug output is also shown.

Note: For more information on troubleshooting Remote Access IPSec VPN refer Most Common L2L and Remote Access IPSec VPN Troubleshooting Solutions.

Clear Security Associations

When you troubleshoot, make sure to clear existent Security Associations after you make a change. In the privileged mode of the PIX, use these commands:

• clear [crypto] ipsec sa—Deletes the active IPSec SAs. The keyword crypto is optional.

• clear [crypto] isakmp sa—Deletes the active IKE SAs. The keyword crypto is optional.

Troubleshooting Commands

The Output Interpreter Tool (registered customers only) (OIT) supports certain show commands. Use the OIT to view an analysis of show command output.

Note: Refer to Important Information on Debug Commands before you use debug commands.

• debug crypto ipsec 7—Displays the IPSec negotiations of Phase 2.

• debug crypto isakmp 7—Displays the ISAKMP negotiations of Phase 1.

Related Information

• Cisco ASA 5500 Series Adaptive Security Appliances Support Page
• Cisco ASA 5500 Series Adaptive Security Appliances Command References
• Cisco PIX 500 Series Security Appliances Support Page
• Cisco PIX 500 Series Security Appliances Command Reference
• Cisco Adaptive Security Device Manager
• IPSec Negotiation/IKE Protocols Support Page
• Cisco VPN Client Support Page
• Cisco PIX Firewall Software
• Cisco Secure PIX Firewall Command References
• Security Product Field Notices (including PIX)
• Requests for Comments (RFCs)
• Technical Support & Documentation - Cisco Systems