IPSec Negotiation IKE Protocols

Configuring IPSec Between a Microsoft Windows 2000 Server and a Cisco Device

Document ID: 14121

Updated: Apr 04, 2008



This document demonstrates how to form an IPSec tunnel with pre-shared keys to join 2 private networks: a private network (192.168.l.X) inside a Cisco device and a private network (10.32.50.X) inside the Microsoft 2000 Server. We assume that traffic from inside the Cisco device and inside the 2000 Server to the Internet (represented here by the 172.18.124.X networks) is flowing prior to beginning this configuration.

You can find detailed information on configuring the Microsoft Windows 2000 server at the Microsoft web site:

Before You Begin


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


There are no specific prerequisites for this document.

Components Used

These configurations were developed and tested using the software and hardware versions below.

  • Microsoft Windows 2000 Server 5.00.2195

  • Cisco 3640 Router with Cisco IOS® Software release c3640-ik2o3s-mz.121-5.T.bin

  • Cisco Secure PIX Firewall with PIX Software Release 5.2.1

  • Cisco VPN 3000 Concentrator with VPN 3000 Concentrator Software Version 2.5.2.F

  • Cisco VPN 5000 Concentrator with VPN 5000 Concentrator Software Version 5.2.19

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.

Network Diagram

This document uses the network setup shown in the diagram below.


Configuring the Microsoft Windows 2000 Server to Work with Cisco Devices

Tasks Performed

This diagram shows the tasks performed in the Microsoft Windows 2000 server configuration:


Step-by-Step Instructions

Once you have followed the configuration instructions on the Microsoft web site, use the following steps to verify that your configuration can work with Cisco devices. Comments and changes are noted with the screen captures.

  1. Click Start > Run > secpol.msc on the Microsoft Windows 2000 Server, and verify the information on the following screens.

    After the instructions on the Microsoft web site were used to configure a 2000 server, the following tunnel information was displayed.

    Note: The example rule is called "to_cisco".


  2. This example rule contains two filters: Microsoft-Cisco and Cisco-Microsoft.


  3. Select the Cisco-Microsoft IP Security Rule, then click Edit to view/add/edit the IP Filter Lists.


  4. The rule's General > Advanced tab has the IKE lifetime (480 minutes = 28800 seconds):


  5. The rule's General > Advanced > Methods tab has the IKE encryption method (DES), IKE hashing (SHA1), and the Diffie-Helman group (Low(1)):


  6. Each filter has 5 tabs:

    1. Authentication Methods (Preshared keys for Internet Key Exchange [IKE]):


    2. Connection Type (LAN):


    3. Filter Action (IPSec):


      Select Filter Action > IPSec tunnel > Edit > Edit, and click Custom:


      Click Settings - IPSec transforms and IPSec lifetime:


    4. IP Filter List - source & destination networks to be encrypted:

      For Cisco-Microsoft:


      For Microsoft-Cisco:


    5. Tunnel Setting - encryption peers:

      For Cisco-Microsoft:


      For Microsoft-Cisco:


Configuring the Cisco Devices

Configure the Cisco router, PIX and VPN Concentrators as shown in the examples below.

Configuring the Cisco 3640 Router

Cisco 3640 Router
Current configuration : 1840 bytes
version 12.1
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
hostname moss
logging rate-limit console 10 except errors
ip subnet-zero
no ip finger
ip audit notify log
ip audit po max-events 100
crypto isakmp policy 1

!--- The following are IOS defaults so they do not appear:
!--- IKE encryption method

encryption des

!--- IKE hashing

hash sha

!--- Diffie-Hellman group

group 1

!--- Authentication method

authentication pre-share

!--- IKE lifetime

lifetime 28800

!--- encryption peer

crypto isakmp key cisco123 address

!--- The following is the IOS default so it does not appear:
!--- IPSec lifetime

crypto ipsec security-association lifetime seconds 3600

!--- IPSec transforms

crypto ipsec transform-set rtpset esp-des esp-md5-hmac 
crypto map rtp 1 ipsec-isakmp 

!--- Encryption peer

set peer
set transform-set rtpset 

!--- Source/Destination networks defined

match address 115
call rsvp-sync
interface Ethernet0/0
ip address
ip nat inside
interface Ethernet0/1
ip address
ip nat outside
crypto map rtp
ip nat pool INTERNET netmask
ip nat inside source route-map nonat pool INTERNET
ip classless
ip route
no ip http server
access-list 101 deny ip
access-list 101 permit ip any

!--- Source/Destination networks defined

access-list 115 permit ip
access-list 115 deny ip any
route-map nonat permit 10
match ip address 101
line con 0
transport input none
line 65 94
line aux 0
line vty 0 4

Configuring PIX

PIX Version 5.2(1)
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password 8Ry2YjIyt7RRXU24 encrypted
passwd 2KFQnbNIdI.2KYOU encrypted
hostname pixfirewall
fixup protocol ftp 21
fixup protocol http 80
fixup protocol h323 1720
fixup protocol rsh 514
fixup protocol smtp 25
fixup protocol sqlnet 1521
fixup protocol sip 5060

!--- Source/Destination networks defined

access-list 115 permit ip 
access-list 115 deny ip any 
pager lines 24
logging on
no logging timestamp
no logging standby
no logging console
no logging monitor
no logging buffered
no logging trap
no logging history
logging facility 20
logging queue 512
interface ethernet0 auto
interface ethernet1 10baset
mtu outside 1500
mtu inside 1500
ip address outside
ip address inside
ip audit info action alarm
ip audit attack action alarm
no failover
failover timeout 0:00:00
failover poll 15
failover ip address outside
failover ip address inside
arp timeout 14400

!--- Except Source/Destination from Network Address Translation (NAT):

nat (inside) 0 access-list 115
route outside 1
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h323 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 
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
sysopt connection permit-ipsec
no sysopt route dnat

!--- IPSec transforms

crypto ipsec transform-set myset esp-des esp-md5-hmac 

!--- IPSec lifetime

crypto ipsec security-association lifetime seconds 3600
crypto map rtpmap 10 ipsec-isakmp

!--- Source/Destination networks

crypto map rtpmap 10 match address 115

!--- Encryption peer

crypto map rtpmap 10 set peer 
crypto map rtpmap 10 set transform-set myset
crypto map rtpmap interface outside
isakmp enable outside

!--- Encryption peer

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

!--- Authentication method

isakmp policy 10 authentication pre-share

!--- IKE encryption method

isakmp policy 10 encryption des

!--- IKE hashing

isakmp policy 10 hash sha

!--- Diffie-Hellman group

isakmp policy 10 group 1

!--- IKE lifetime

isakmp policy 10 lifetime 28800
telnet timeout 5
ssh timeout 5
terminal width 80
: end

Configuring the VPN 3000 Concentrator

Use the menu options and parameters shown below to configure the VPN Concentrator as needed.

  • To add an IKE proposal, select Configuration > System > Tunneling Protocols > IPSec > IKE Proposals > Add a proposal.

    Proposal Name = DES-SHA
    !--- Authentication method
    Authentication Mode = Preshared Keys
    !--- IKE hashing
    Authentication Algorithm = SHA/HMAC-160
    !--- IKE encryption method
    Encryption Algorithm = DES-56
    !--- Diffie-Hellman group
    Diffie Hellman Group = Group 1 (768-bits) 
    Lifetime Measurement = Time
    Date Lifetime = 10000
    !--- IKE lifetime
    Time Lifetime = 28800 
  • To define the LAN-to-LAN tunnel, select Configuration > System > Tunneling Protocols > IPSec LAN-to-LAN.

    Name = to_2000
    Interface = Ethernet 2 (Public)
    !--- Encryption peer
    Peer =
    !--- Authentication method
    Digital Certs = none (Use Pre-shared Keys)
    Pre-shared key = cisco123
    !--- IPSec transforms
    Authentication = ESP/MD5/HMAC-128
    Encryption = DES-56
    !--- Use the IKE proposal
    IKE Proposal = DES-SHA
    Autodiscovery = off
    !--- Source network defined
    Local Network 
    Network List = Use IP Address/Wildcard-mask below
    IP Address
    Wildcard Mask =
    !--- Destination network defined
    Remote Network
    Network List = Use IP Address/Wildcard-mask below
    IP Address 
    Wildcard Mask 
  • To modify the security association, select Configuration > Policy Management > Traffic Management > Security Associations > Modify.

    SA Name = L2L-to_2000
    Inheritance = From Rule
    IPSec Parameters
    !--- IPSec transforms
    Authentication Algorithm = ESP/MD5/HMAC-128
    Encryption Algorithm = DES-56
    Encapsulation Mode = Tunnel
    PFS = Disabled
    Lifetime Measurement = Time
    Data Lifetime = 10000
    !--- IPSec lifetime
    Time Lifetime = 3600
    Ike Parameters
    !--- Encryption peer
    IKE Peer =
    Negotiation Mode = Main
    !--- Authentication method
    Digital Certificate = None (Use Preshared Keys)
    !--- Use the IKE proposal
    IKE Proposal DES-SHA 

Configuring the VPN 5000 Concentrator

VPN 5000 Concentrator
[ IP Ethernet 1:0 ]
Mode = Routed
SubnetMask =
IPAddress =

[ General ]
IPSecGateway =
DeviceName = "cisco"
EthernetAddress = 00:00:a5:f0:c8:00
DeviceType = VPN 5002/8 Concentrator
ConfiguredOn = Timeserver not configured
ConfiguredFrom = Command Line, from Console

[ IP Ethernet 0:0 ]
Mode = Routed
SubnetMask =
IPAddress =

[ Tunnel Partner VPN 1 ]

!--- Encryption peer

Partner =

!--- IPSec lifetime

KeyLifeSecs = 3600

BindTo = "ethernet 1:0"

!--- Authentication method

SharedKey = "cisco123"
KeyManage = Auto

!--- IPSec transforms

Transform = esp(md5,des)
Mode = Main

!--- Destination network defined

Peer = ""

!--- Source network defined

LocalAccess = ""

[ IP Static ] VPN 1 1

[ IP VPN 1 ]
Mode = Routed
Numbered = Off

[ IKE Policy ]

!--- IKE hashing, encryption, Diffie-Hellman group

Protection = SHA_DES_G1

Configuration size is 1088 out of 65500 bytes.


There is currently no verification procedure available for this configuration.


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

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.

Cisco 3640 Router

  • debug crypto engine - Shows debug messages about crypto engines, which perform encryption and decryption.

  • debug crypto isakmp - Shows messages about IKE events.

  • debug crypto ipsec - Shows IPSec events.

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

  • show crypto ipsec sa - Shows the settings used by current security associations.

  • clear crypto isakmp - (from configuration mode) Clears all active IKE connections.

  • clear crypto sa - (from configuration mode) Deletes all IPSec security associations.


  • debug crypto ipsec - Shows the IPSec negotiations of phase 2.

  • debug crypto isakmp - Shows the Internet Security Association and Key Management Protocol (ISAKMP) negotiations of phase 1.

  • debug crypto engine - Shows the traffic that is encrypted.

  • show crypto ipsec sa - Shows the phase 2 security associations.

  • show crypto isakmp sa - Shows the phase 1 security associations.

  • clear crypto isakmp - (from configuration mode) Clears Internet Key Exchange (IKE) security associations.

  • clear crypto ipsec sa - (from configuration mode) Clears IPSec security associations.

VPN 3000 Concentrator

  • - Start the VPN 3000 Concentrator debug by selecting Configuration > System > Events > Classes > Modify (Severity to Log=1-13, Severity to Console=1-3): IKE, IKEDBG, IKEDECODE, IPSEC, IPSECDBG, IPSECDECODE

  • - The event log can be cleared or retrieved by selecting Monitoring > Event Log.

  • - The LAN-to-LAN tunnel traffic can be monitored in Monitoring > Sessions.

  • - The tunnel can be cleared in Administration > Administer Sessions > LAN-to-LAN sessions > Actions - Logout.

VPN 5000 Concentrator

  • vpn trace dump all - Shows information about all matching VPN connections, including information about the time, the VPN number, the real IP address of the peer, which scripts have been run, and in the case of an error, the routine and line number of the software code where the error occurred.

  • show vpn statistics - Shows the following information for Users, Partners, and the Total for both. (For modular models, the display includes a section for each module slot.) Current Active - The current active connections. In Negot - The currently negotiating connections. High Water - The highest number of concurrent active connections since the last reboot. Running Total - The total number of successful connections since the last reboot. Tunnel Starts - The number of tunnel starts. Tunnel OK - The number of tunnels for which there were no errors. Tunnel Error - The number of tunnels with errors.

  • show vpn statistics verbose - Shows ISAKMP negotiation statistics, and many more active connection statistics.

Related Information

Updated: Apr 04, 2008
Document ID: 14121