IPSec - PIX to Cisco VPN Client Wild-card, Pre-shared, Mode Configuration with Extended Authentication

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Updated:September 26, 2008

Document ID:10967

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Introduction

Prerequisites

Requirements

Components Used

Conventions

Background Information

Configure

Network Diagram

Configurations

Verify

Troubleshoot

Troubleshooting Commands

PIX Debug Sample

Debugs with VPN Client 4.x

Debugs with VPN Client 1.1

Related Information

Introduction

This configuration example demonstrates how to connect a VPN Client to a PIX Firewall using wildcards, mode-config, the sysopt connection permit-ipsec command, and extended authentication (Xauth).

In order to see the TACACS+ and RADIUS configuration for PIX 6.3 and later, refer to TACACS+ and RADIUS for PIX 6.3 and PIX/ASA 7.x Configuration Example.

The VPN Client supports Advanced Encryption Standard (AES) as an encryption algorithm in Cisco VPN Client release 3.6.1 and later and with PIX Firewall 6.3. The VPN Client supports key sizes of 128 bits and 256 bits only. For more information on how to configure AES, refer to How to Configure the Cisco VPN Client to PIX with AES.

Refer to PIX/ASA 7.x and Cisco VPN Client 4.x for Windows with Microsoft Windows 2003 IAS RADIUS Authentication Configuration Example 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 using a Microsoft Windows 2003 Internet Authentication Service (IAS) RADIUS server.

Refer to IPsec Between a VPN 3000 Concentrator and a VPN Client 4.x for Windows using RADIUS for User Authentication and Accounting Configuration Example to establish an IPsec tunnel between a Cisco VPN 3000 Concentrator and a Cisco VPN Client 4.x for Windows using RADIUS for user authentication and accounting.

Refer to Configuring IPsec Between a Cisco IOS Router and a Cisco VPN Client 4.x for Windows Using RADIUS for User Authentication to configure a connection between a router and the Cisco VPN Client 4.x using RADIUS for user authentication.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

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

Cisco VPN Client 4.x. This product has advanced VPN features, unlike the Cisco Secure VPN Client 1.x.
PIX Firewall 515E version 6.3(3).

Note: Encryption technology is subject to export controls. It is your responsibility to know the law regarding export of encryption technology. For more information, refer to the Bureau of Export Administration web site . If you have any questions regarding export control, please send an email to export@cisco.com.

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.

Conventions

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

Background Information

The sysopt connection permit-ipsec command implicitly permits any packet that comes from an IPsec tunnel to bypass the checking of an associated access-list, conduit, or access-group command for IPsec connections. Xauth authenticates the IPsec user to an external TACACS+ or RADIUS server. In addition to the wild-card pre-shared key, the user must provide a username/password.

A user with a VPN Client receives an IP address from their ISP. This is replaced by an IP address from the IP address pool on the PIX. The user has access to everything on the inside of the firewall, including networks. Users who do not run the VPN Client can connect only to the web server using the outside address provided by the static assignment.

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) to find more information on the commands used in this document.

Network Diagram

This document uses this network setup:

Network Diagram Notes

Internet hosts which access the web server using the global IP address 192.168.1.1 are authenticated even if a VPN connection is not established. This traffic is not encrypted.
VPN Clients are able to access all hosts on the inside network (10.89.129.128 /25) once their IPsec tunnel is established. All traffic from the VPN Client to the PIX Firewall is encrypted. Without an IPsec tunnel, they are only able to access the web server via its global IP address but are still required to authenticate.
VPN Clients come from the Internet and their IP addresses are not known in advance.

Configurations

This document uses these configurations.

PIX Configuration 6.3(3)
VPN Client 4.0.5 Configuration
VPN Client 3.5 Configuration
VPN Client 1.1 Configuration

PIX Configuration 6.3(3)
pixfirewall#show run : Saved : PIX Version 6.3(3) interface ethernet0 100full interface ethernet1 100full nameif ethernet0 outside security0 nameif ethernet1 inside security100 enable password 8Ry2YjIyt7RRXU24 encrypted passwd 2KFQnbNIdI.2KYOU encrypted hostname pixfirewall fixup protocol dns maximum-length 512 fixup protocol ftp 21 fixup protocol h323 h225 1720 fixup protocol h323 ras 1718-1719 fixup protocol http 80 fixup protocol rsh 514 fixup protocol rtsp 554 fixup protocol sip 5060 fixup protocol sip udp 5060 fixup protocol skinny 2000 fixup protocol smtp 25 fixup protocol sqlnet 1521 fixup protocol tftp 69 names !--- Do not use Network Address Translation (NAT) for inside-to-pool !--- traffic. This should not go through NAT. access-list 101 permit ip 10.89.129.128 255.255.255.240 10.89.129.192 255.255.255.240 !--- Permits Internet Control Message Protocol (ICMP) !--- Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) !--- traffic from any host on the Internet (non-VPN) to the web server. access-list 120 permit icmp any host 10.89.129.131 access-list 120 permit tcp any host 10.89.129.131 access-list 120 permit udp any host 10.89.129.131 pager lines 24 mtu outside 1500 mtu inside 1500 ip address outside 192.168.1.1 255.255.255.0 ip address inside 10.89.129.194 255.255.255.240 ip audit info action alarm ip audit attack action alarm !--- Specifies the inside IP address range to be assigned !--- to the VPN Clients. ip local pool VPNpool 10.89.129.200-10.89.129.204 no failover failover timeout 0:00:00 failover poll 15 no failover ip address outside no failover ip address inside pdm history enable arp timeout 14400 !--- Defines a pool of global addresses to be used by NAT. global (outside) 1 192.168.1.6-192.168.1.10 nat (inside) 0 access-list 101 nat (inside) 1 0.0.0.0 0.0.0.0 0 0 !--- Specifies which outside IP address to apply to the web server. static (inside,outside) 192.168.1.11 10.89.129.131 netmask 255.255.255.255 0 0 !--- Apply ACL 120 to the outside interface in the inbound direction. access-group 120 in interface outside !--- Defines a default route for the PIX. route outside 0.0.0.0 0.0.0.0 192.168.1.3 1 !--- Defines a route for traffic within the PIX's !--- subnet to reach other inside hosts. route inside 10.89.129.128 255.255.255.128 10.89.129.193 1 timeout xlate 3:00:00 timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h225 1:00:00 timeout h323 0:05:00 mgcp 0:05:00 sip 0:30:00 sip_media 0:02:00 timeout uauth 0:05:00 absolute aaa-server TACACS+ protocol tacacs+ aaa-server RADIUS protocol radius aaa-server LOCAL protocol local !--- Authentication, authorization, and accounting (AAA) statements !--- for authentication. !--- Use either of these statements to define the protocol of the group AuthInbound. !--- You cannot use both. aaa-server AuthInbound protocol tacacs+ !--- OR aaa-server AuthInbound protocol radius !--- After you define the protocol of the group AuthInbound, define !--- a server of the same type. !--- In this case we specify the TACACS+ server and key of "secretkey". aaa-server AuthInbound (inside) host 10.89.129.134 secretkey timeout 10 !--- Authenticate HTTP, FTP, and Telnet traffic to the web server. aaa authentication include http outside 10.89.129.131 255.255.255.255 0.0.0.0 0.0.0.0 AuthInbound aaa authentication include ftp outside 10.89.129.131 255.255.255.255 0.0.0.0 0.0.0.0 AuthInbound aaa authentication include telnet outside 10.89.129.131 255.255.255.255 0.0.0.0 0.0.0.0 AuthInbound no snmp-server location no snmp-server contact snmp-server community public no snmp-server enable traps floodguard enable !--- Trust IPsec traffic and avoid going through ACLs/NAT. sysopt connection permit-ipsec !--- IPsec and dynamic map configuration. crypto ipsec transform-set myset esp-des esp-md5-hmac crypto dynamic-map dynmap 10 set transform-set myset crypto map mymap 10 ipsec-isakmp dynamic dynmap !--- Assign IP address for VPN 1.1 Clients. crypto map mymap client configuration address initiate crypto map mymap client configuration address respond !--- Use the AAA server for authentication (AuthInbound). crypto map mymap client authentication AuthInbound !--- Apply the IPsec/AAA/ISAKMP configuration to the outside interface. crypto map mymap interface outside isakmp enable outside !--- Pre-shared key for VPN 1.1 Clients. isakmp key ******** address 0.0.0.0 netmask 0.0.0.0 isakmp identity address !--- Assign address from "VPNpool" pool for VPN 1.1 Clients. isakmp client configuration address-pool local VPNpool outside !--- ISAKMP configuration for VPN Client 3.x/4.x. isakmp policy 10 authentication pre-share isakmp policy 10 encryption des isakmp policy 10 hash md5 isakmp policy 10 group 2 isakmp policy 10 lifetime 86400 !--- ISAKMP configuration for VPN Client 1.x. isakmp policy 20 authentication pre-share isakmp policy 20 encryption des isakmp policy 20 hash md5 isakmp policy 20 group 1 isakmp policy 20 lifetime 86400 !--- Assign addresses from "VPNpool" for VPN Client 3.x/4.x. vpngroup vpn3000 address-pool VPNpool vpngroup vpn3000 idle-time 1800 !--- Group password for VPN Client 3.x/4.x (not shown in configuration). vpngroup vpn3000 password ******** telnet timeout 5 ssh timeout 5 console timeout 0 terminal width 80 Cryptochecksum:ba54c063d94989cbd79076955dbfeefc : end pixfirewall#

PIX Configuration 6.3(3)

pixfirewall#show run
: Saved
:
PIX Version 6.3(3)
interface ethernet0 100full
interface ethernet1 100full
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password 8Ry2YjIyt7RRXU24 encrypted
passwd 2KFQnbNIdI.2KYOU encrypted
hostname pixfirewall
fixup protocol dns maximum-length 512
fixup protocol ftp 21
fixup protocol h323 h225 1720
fixup protocol h323 ras 1718-1719
fixup protocol http 80
fixup protocol rsh 514
fixup protocol rtsp 554
fixup protocol sip 5060
fixup protocol sip udp 5060
fixup protocol skinny 2000
fixup protocol smtp 25
fixup protocol sqlnet 1521
fixup protocol tftp 69
names

!--- Do not use Network Address Translation (NAT) for inside-to-pool !--- traffic. This should not go through NAT.

access-list 101 permit ip 10.89.129.128 255.255.255.240 10.89.129.192 255.255.255.240

!--- Permits Internet Control Message Protocol (ICMP) !--- Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) !--- traffic from any host on the Internet (non-VPN) to the web server.

access-list 120 permit icmp any host 10.89.129.131
access-list 120 permit tcp any host 10.89.129.131
access-list 120 permit udp any host 10.89.129.131

pager lines 24
mtu outside 1500
mtu inside 1500
ip address outside 192.168.1.1 255.255.255.0
ip address inside 10.89.129.194 255.255.255.240
ip audit info action alarm
ip audit attack action alarm

!--- Specifies the inside IP address range to be assigned !--- to the VPN Clients.

ip local pool VPNpool 10.89.129.200-10.89.129.204
no failover
failover timeout 0:00:00
failover poll 15
no failover ip address outside
no failover ip address inside
pdm history enable
arp timeout 14400

!--- Defines a pool of global addresses to be used by NAT.

global (outside) 1 192.168.1.6-192.168.1.10

nat (inside) 0 access-list 101
nat (inside) 1 0.0.0.0 0.0.0.0 0 0

!--- Specifies which outside IP address to apply to the web server.

static (inside,outside) 192.168.1.11 10.89.129.131 netmask 255.255.255.255 0 0

!--- Apply ACL 120 to the outside interface in the inbound direction.

access-group 120 in interface outside

!--- Defines a default route for the PIX.

route outside 0.0.0.0 0.0.0.0 192.168.1.3 1

!--- Defines a route for traffic within the PIX's !--- subnet to reach other inside hosts.

route inside 10.89.129.128 255.255.255.128 10.89.129.193 1

timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h225 1:00:00
timeout h323 0:05:00 mgcp 0:05:00 sip 0:30:00 sip_media 0:02:00
timeout uauth 0:05:00 absolute
aaa-server TACACS+ protocol tacacs+
aaa-server RADIUS protocol radius
aaa-server LOCAL protocol local


!--- Authentication, authorization, and accounting (AAA) statements !--- for authentication. !--- Use either of these statements to define the protocol of the group AuthInbound. !--- You cannot use both. 
aaa-server AuthInbound protocol tacacs+


!--- OR

aaa-server AuthInbound protocol radius


!--- After you define the protocol of the group AuthInbound, define !--- a server of the same type. !--- In this case we specify the TACACS+ server and key of "secretkey".

aaa-server AuthInbound (inside) host 10.89.129.134 secretkey timeout 10


!--- Authenticate HTTP, FTP, and Telnet traffic to the web server.

aaa authentication include http outside 
10.89.129.131 255.255.255.255 0.0.0.0 0.0.0.0 AuthInbound

aaa authentication include ftp outside
 10.89.129.131 255.255.255.255 0.0.0.0 0.0.0.0 AuthInbound

aaa authentication include telnet outside 
10.89.129.131 255.255.255.255 0.0.0.0 0.0.0.0 AuthInbound

no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable

!--- Trust IPsec traffic and avoid going through ACLs/NAT.

sysopt connection permit-ipsec

!--- IPsec and dynamic map configuration.

crypto ipsec transform-set myset esp-des esp-md5-hmac
crypto dynamic-map dynmap 10 set transform-set myset
crypto map mymap 10 ipsec-isakmp dynamic dynmap

!--- Assign IP address for VPN 1.1 Clients.

crypto map mymap client configuration address initiate
crypto map mymap client configuration address respond

!--- Use the AAA server for authentication (AuthInbound).

crypto map mymap client authentication AuthInbound

!--- Apply the IPsec/AAA/ISAKMP configuration to the outside interface.

crypto map mymap interface outside
isakmp enable outside

!--- Pre-shared key for VPN 1.1 Clients.

isakmp key ******** address 0.0.0.0 netmask 0.0.0.0
isakmp identity address

!--- Assign address from "VPNpool" pool for VPN 1.1 Clients.

isakmp client configuration address-pool local VPNpool outside

!--- ISAKMP configuration for VPN Client 3.x/4.x.

isakmp policy 10 authentication pre-share
isakmp policy 10 encryption des
isakmp policy 10 hash md5
isakmp policy 10 group 2
isakmp policy 10 lifetime 86400

!--- ISAKMP configuration for VPN Client 1.x.

isakmp policy 20 authentication pre-share
isakmp policy 20 encryption des
isakmp policy 20 hash md5
isakmp policy 20 group 1
isakmp policy 20 lifetime 86400

!--- Assign addresses from "VPNpool" for VPN Client 3.x/4.x.

vpngroup vpn3000 address-pool VPNpool

vpngroup vpn3000 idle-time 1800


!--- Group password for VPN Client 3.x/4.x (not shown in configuration).

vpngroup vpn3000 password ********
telnet timeout 5
ssh timeout 5
console timeout 0
terminal width 80
Cryptochecksum:ba54c063d94989cbd79076955dbfeefc
: end
pixfirewall#

VPN Client 4.0.5 Configuration

Complete these steps to configure the VPN Client 4.0.5.

Select Start > Programs > Cisco Systems VPN Client > VPN Client.
Click New to launch the Create New VPN Connection Entry window.
Enter the name of the Connection Entry along with a description. Enter the outside IP address of the PIX Firewall in the Host box. Then enter the VPN Group name and password and click Save.
From the VPN Client main window, click on the connection you would like to use and click the Connect button.
When prompted, enter the Username and Password information for Xauth and click OK to connect to the remote network.

VPN Client 3.5 Configuration

Complete these steps to configure the VPN Client 3.5 configuration.

Select Start > Programs > Cisco Systems VPN Client > VPN Dialer.
Click New to launch the New Connection Entry Wizard.
Enter the name of your new connection entry and click Next.
Enter the host name or IP address of the server that is used to connect to the remote server and click Next.
Select Group Access Information and enter the Name and Password that is used to authenticate your access to the remote server. Click Next.
Click Finish to save the new entry.
Select the Connection Entry in the dialer and click Connect.
When prompted, enter the Username and Password information for Xauth and click OK to connect to the remote network.

VPN Client 1.1 Configuration
Network Security policy: 1- TACconn My Identity Connection security: Secure Remote Party Identity and addressing ID Type: IP subnet 10.89.129.128 255.255.255.128 Port all Protocol all Connect using secure tunnel ID Type: IP address 192.168.1.1 Pre-shared Key=cisco1234 Authentication (Phase 1) Proposal 1 Authentication method: pre-shared key Encryp Alg: DES Hash Alg: MD5 SA life: Unspecified Key Group: DH 1 Key exchange (Phase 2) Proposal 1 Encapsulation ESP Encrypt Alg: DES Hash Alg: MD5 Encap: tunnel SA life: Unspecified no AH 2- Other Connections Connection security: Non-secure Local Network Interface Name: Any IP Addr: Any Port: All

VPN Client 1.1 Configuration

Network Security policy: 
 1- TACconn
     My Identity
          Connection security: Secure
          Remote Party Identity and addressing
          ID Type: IP subnet
          10.89.129.128
          255.255.255.128
          Port all Protocol all


     Connect using secure tunnel

          ID Type: IP address
          192.168.1.1


     Pre-shared Key=cisco1234


     Authentication (Phase 1)

     Proposal 1
         Authentication method: pre-shared key
         Encryp Alg: DES
         Hash Alg: MD5
         SA life: Unspecified
         Key Group: DH 1

     Key exchange (Phase 2)

     Proposal 1
         Encapsulation ESP
         Encrypt Alg: DES
         Hash Alg: MD5
         Encap: tunnel
         SA life: Unspecified
         no AH

 2- Other Connections
        Connection security: Non-secure
        Local Network Interface
          Name: Any
          IP Addr: Any
          Port: All

Add Accounting

The syntax of the command to add accounting is:

aaa accounting include acctg_service
   inbound|outbound l_ip l_mask [f_ip f_mask] server_tag

For example, in the PIX configuration, this command is added:

aaa accounting include any inbound 
0.0.0.0 0.0.0.0 0.0.0.0 0.0.0.0 AuthInbound

Note: The sysopt connection permit-ipsec command, not the sysopt ipsec pl-compatible command, is necessary for Xauth accounting to work. Xauth accounting does not work with only the sysopt ipsec pl-compatible command. Xauth accounting is valid for TCP connections, not ICMP or UDP.

This output is an example of TACACS+ accounting records:

07/27/2004 15:17:54 cisco_customer Default Group 10.89.129.200 stop 15 .. 99 1879 .. .. 
   0x5 .. PIX 10.89.129.194 telnet 
07/27/2004 15:17:39 cisco_customer Default Group 10.89.129.200 start .. .. .. .. .. .. 
   0x5 .. PIX 10.89.129.194 telnet

Verify

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.

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

Enable the Cisco Secure Log Viewer in order to see the client-side debugs.

debug crypto ipsec—Used to see the IPsec negotiations of phase 2.
debug crypto isakmp—Used to see the ISAKMP negotiations of phase 1.