Configuring IPSec Router-to-Router with NAT Overload and Cisco Secure VPN Client
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Contents
Introduction
This sample configuration encrypts traffic from the network behind Light to the network behind House (the 192.168.100.x to 192.168.200.x network). Network Address Translation (NAT) overload is also done. Encrypted VPN Client connections are allowed into Light with wild-card, pre-shared keys and mode-config. Traffic to the Internet is translated, but not encrypted.
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:
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Cisco IOS® Software Release 12.2.7 and 12.2.8T
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Cisco Secure VPN Client 1.1 (shown as 2.1.12 in the IRE client Help > About menu)
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Cisco 3600 routers
Note: If you use the Cisco 2600 Series Routers for this kind of VPN scenario, then the routers must be installed with crypto IPsec VPN IOS images.
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.
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:
Configurations
This document uses these configurations.
| Light Configuration |
|---|
Current configuration : 2047 bytes ! version 12.2 service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname Light ! boot system flash:c3660-ik9o3s-mz.122-8T ! ip subnet-zero ! ip audit notify log ip audit po max-events 100 ip ssh time-out 120 ip ssh authentication-retries 3 ! !--- IPsec Internet Security Association and !--- Key Management Protocol (ISAKMP) policy. crypto isakmp policy 5 hash md5 authentication pre-share !--- ISAKMP key for static LAN-to-LAN tunnel !--- without extended authenticaton (xauth). crypto isakmp key cisco123 address 10.64.10.45 no-xauth !--- ISAKMP key for the dynamic VPN Client. crypto isakmp key 123cisco address 0.0.0.0 0.0.0.0 !--- Assign the IP address to the VPN Client. crypto isakmp client configuration address-pool local test-pool ! ! ! crypto ipsec transform-set testset esp-des esp-md5-hmac ! crypto dynamic-map test-dynamic 10 set transform-set testset ! ! !--- VPN Client mode configuration negotiation, !--- such as IP address assignment and xauth. crypto map test client configuration address initiate crypto map test client configuration address respond !--- Static crypto map for the LAN-to-LAN tunnel. crypto map test 5 ipsec-isakmp set peer 10.64.10.45 set transform-set testset !--- Include the private network-to-private network traffic !--- in the encryption process. match address 115 !--- Dynamic crypto map for the VPN Client. crypto map test 10 ipsec-isakmp dynamic test-dynamic ! call rsvp-sync ! ! ! ! ! fax interface-type modem mta receive maximum-recipients 0 ! controller E1 2/0 ! ! ! interface FastEthernet0/0 ip address 10.64.10.44 255.255.255.224 ip nat outside duplex auto speed auto crypto map test ! interface FastEthernet0/1 ip address 192.168.100.1 255.255.255.0 ip nat inside duplex auto speed auto ! interface BRI4/0 no ip address shutdown ! interface BRI4/1 no ip address shutdown ! interface BRI4/2 no ip address shutdown ! interface BRI4/3 no ip address shutdown ! !--- Define the IP address pool for the VPN Client. ip local pool test-pool 192.168.1.1 192.168.1.254 !--- Exclude the private network and VPN Client !--- traffic from the NAT process. ip nat inside source route-map nonat interface FastEthernet0/0 overload ip classless ip route 0.0.0.0 0.0.0.0 10.64.10.33 ip http server ip pim bidir-enable ! !--- Exclude the private network and VPN Client !--- traffic from the NAT process. access-list 110 deny ip 192.168.100.0 0.0.0.255 192.168.200.0 0.0.0.255 access-list 110 deny ip 192.168.100.0 0.0.0.255 192.168.1.0 0.0.0.255 access-list 110 permit ip 192.168.100.0 0.0.0.255 any !--- Include the private network-to-private network traffic !--- in the encryption process. access-list 115 permit ip 192.168.100.0 0.0.0.255 192.168.200.0 0.0.0.255 ! !--- Exclude the private network and VPN Client !--- traffic from the NAT process. route-map nonat permit 10 match ip address 110 ! ! dial-peer cor custom ! ! ! ! ! line con 0 line 97 108 line aux 0 line vty 0 4 ! end |
| House Configuration |
|---|
Current configuration : 1689 bytes ! version 12.2 service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname house ! boot system flash:c3660-jk8o3s-mz.122-7.bin ! ip subnet-zero ! ! no ip domain-lookup ! ip audit notify log ip audit po max-events 100 ip ssh time-out 120 ip ssh authentication-retries 3 ! !--- IPsec ISAKMP policy. crypto isakmp policy 5 hash md5 authentication pre-share !--- ISAKMP key for static LAN-to-LAN tunnel without xauth authenticaton. crypto isakmp key cisco123 address 10.64.10.44 no-xauth ! ! crypto ipsec transform-set testset esp-des esp-md5-hmac ! !--- Static crypto map for the LAN-to-LAN tunnel. crypto map test 5 ipsec-isakmp set peer 10.64.10.44 set transform-set testset !--- Include the private network-to-private network traffic !--- in the encryption process. match address 115 ! call rsvp-sync cns event-service server ! ! ! ! ! fax interface-type modem mta receive maximum-recipients 0 ! ! ! interface FastEthernet0/0 ip address 10.64.10.45 255.255.255.224 ip nat outside duplex auto speed auto crypto map test ! interface FastEthernet0/1 ip address 192.168.200.1 255.255.255.0 ip nat inside duplex auto speed auto ! interface BRI2/0 no ip address shutdown ! interface BRI2/1 no ip address shutdown ! interface BRI2/2 no ip address shutdown ! interface BRI2/3 no ip address shutdown ! interface FastEthernet4/0 no ip address shutdown duplex auto speed auto ! !--- Exclude the private network traffic !--- from the dynamic (dynamic association to a pool) NAT process. ip nat inside source route-map nonat interface FastEthernet0/0 overload ip classless ip route 0.0.0.0 0.0.0.0 10.64.10.33 no ip http server ip pim bidir-enable ! !--- Exclude the private network traffic from the NAT process. access-list 110 deny ip 192.168.200.0 0.0.0.255 192.168.100.0 0.0.0.255 access-list 110 permit ip 192.168.200.0 0.0.0.255 any !--- Include the private network-to-private network traffic !--- in the encryption process. access-list 115 permit ip 192.168.200.0 0.0.0.255 192.168.100.0 0.0.0.255 !--- Exclude the private network traffic from the NAT process. route-map nonat permit 10 match ip address 110 ! ! ! dial-peer cor custom ! ! ! ! ! line con 0 line aux 0 line vty 0 4 login ! end |
| VPN Client Configuration |
|---|
Network Security policy:
1- TOLIGHT
My Identity
Connection security: Secure
Remote Party Identity and addressing
ID Type: IP subnet
192.168.100.0
255.255.255.0
Port all Protocol all
Connect using secure tunnel
ID Type: IP address
10.64.10.44
Pre-shared Key=123cisco
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 |
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.
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show crypto ipsec sa—Shows the phase 2 Security Associations (SAs).
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show crypto isakmp sa—Shows the phase 1 SAs.
Troubleshoot
Use this section to troubleshoot your configuration.
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.
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debug crypto ipsec—Shows the IPsec negotiations of phase 2.
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debug crypto isakmp—Shows the ISAKMP negotiations of phase 1.
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debug crypto engine—Shows the traffic that is encrypted.
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clear crypto isakmp—Clears the SAs related to phase 1.
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clear crypto sa—Clears the SAs related to phase 2.
Related Information
Revision History
| Revision | Publish Date | Comments |
|---|---|---|
1.0 |
01-May-2007 |
Initial Release |
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