Document ID: 64693
Updated: Oct 14, 2009
Contents
Introduction
This document describes how to configure LAN-to-LAN sessions between PIX Security Appliances, and also allows for a VPN Client to access the spoke network (PIX3) through the hub (PIX1) with Cisco Secure ACS for windows with TACACS+ authentication. In addition, this document demonstrates the configuration for a static LAN-to-LAN tunnel with VPN Client to spoke connectivity through the hub PIX Security Appliance. PIX version 7.0 improves support for spoke-to-spoke VPN communications. PIX 7.0 provides the ability for encrypted traffic to enter and leave the same interface.
The same-security-traffic command permits traffic to enter and exit the same interface when used with the intra-interface keyword, which enables spoke-to-spoke VPN support. Refer to the Permitting Intra-Interface Traffic section in the Cisco Security Appliance Command Line Configuration Guide for more information.
Note: In order to avoid the overlapping of IP addresses in the network, assign the entirely different pool of IP addresses to the VPN Client, for example, 10.x.x.x , 172.16.x.x, or 192.168.x.x. This IP addressing scheme helps to troubleshoot your network.
Note: In PIX version 7.2 and later, the intra-interface keyword allows all traffic to enter and exit the same interface and not just IPsec traffic.
Note: This document is for PIX/ASA 7.x configuration. Refer to Configuring IPSec Between Hub and Remote PIXes with VPN Client and Extended Authentication in order to learn more about the PIX 6.x configuration.
Refer to PIX/ASA 7.x and VPN Client for Public Internet VPN on a Stick Configuration Example in order to learn more about the scenario where the hub PIX redirects the traffic from the VPN Client to the Internet.
Refer to IPsec Tunnel Between PIX 7.x and VPN 3000 Concentrator Configuration Example in order to learn more about the scenario where the LAN-to-LAN tunnel between PIX and the Cisco VPN Concentrator.
Refer to PIX/ASA 7.x Security Appliance to an IOS Router LAN-to-LAN IPsec Tunnel Configuration Example in order to learn more about the scenario where the LAN-to-LAN tunnel between PIX/ASA and a Cisco IOS® router.
Prerequisites
Requirements
The hub PIX Security Appliance needs to run version 7.0 or later.
Note: Refer to the Guide for Cisco PIX 6.2 and 6.3 Users Upgrading to Cisco PIX Software Version 7.0 for more information on how to upgrade the PIX Security Appliance to version 7.0.
Components Used
The information in this document is based on these software and hardware versions:
-
PIX - 515 version 7.0.1 (PIX1)
-
VPN Client version 4.6.02.0011
-
PIX - 515 version 6.3.4 (PIX3)
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.
Caveats
-
Cisco bug ID CSCeh29328 (registered customers only) —VPN Client mode configuration attributes are not enforced when you disable XAUTH.
-
Cisco bug ID CSCeh69389 (registered customers only) —Split-tunnel ACLs are not converted to standard ACLs when you upgrade to PIX 7.0.
Configure
This section presents you with the information to use in order to configure the features this document describes.
Note: In order to find additional information on the commands this document uses, use the Command Lookup Tool (registered customers only) .
Note: For a PIX Security Appliance 7.x LAN-to-LAN (L2L) VPN configuration, you must specify the <name> of the tunnel group as the Remote peer IP Address in the tunnel-group <name> type ipsec-l2l command for creating and managing the database of connection-specific records for IPsec.
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 have been used in a lab environment.
Configurations
This document uses these configurations:
| PIX1 |
|---|
PIX Version 7.0(1) no names ! interface Ethernet0 nameif outside security-level 0 ip address 172.18.124.170 255.255.255.0 ! interface Ethernet1 nameif inside security-level 100 ip address 10.10.10.1 255.255.255.0 ! interface Ethernet2 shutdown nameif intf2 security-level 4 no ip address ! interface Ethernet3 shutdown nameif intf3 security-level 6 no ip address ! interface Ethernet4 shutdown nameif intf4 security-level 8 no ip address ! interface Ethernet5 shutdown nameif intf5 security-level 10 no ip address ! enable password 9jNfZuG3TC5tCVH0 encrypted passwd OnTrBUG1Tp0edmkr encrypted hostname PIX1 domain-name cisco.com boot system flash:/image.bin ftp mode passive !--- Command to permit IPsec traffic to enter and exit the same interface. same-security-traffic permit intra-interface !--- Access-list for interesting traffic to be encrypted between !--- the hub (PIX1) and spoke (PIX3) networks. access-list 100 extended permit ip 10.10.10.0 255.255.255.0 10.11.10.0 255.255.255.0 !--- Access-list for interesting traffic to be encrypted !--- between the VPN Client networks and spoke (PIX3) networks. access-list 100 extended permit ip 192.168.10.0 255.255.255.0 10.11.10.0 255.255.255.0 !--- Access-list for interesting traffic to bypass the !--- Network Address Translation (NAT) process. access-list nonat extended permit ip 10.10.10.0 255.255.255.0 10.11.10.0 255.255.255.0 access-list nonat extended permit ip 10.10.10.0 255.255.255.0 192.168.10.0 255.255.255.0 !--- Standard access-list to allow split-tunnel for the VPN Clients. access-list splittunnel standard permit 10.10.10.0 255.255.255.0 access-list splittunnel standard permit 10.11.10.0 255.255.255.0 pager lines 24 mtu outside 1500 mtu inside 1500 mtu intf2 1500 mtu intf3 1500 mtu intf4 1500 mtu intf5 1500 !--- Address pool for the VPN Clients. ip local pool vpnpool 192.168.10.1-192.168.10.254 no failover monitor-interface outside monitor-interface inside monitor-interface intf2 monitor-interface intf3 monitor-interface intf4 monitor-interface intf5 asdm history enable arp timeout 14400 nat-control global (outside) 1 interface !--- Bypass NAT process for IPsec traffic. nat (inside) 0 access-list nonat nat (inside) 1 10.10.10.0 255.255.255.0 route outside 0.0.0.0 0.0.0.0 172.18.124.1 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 timeout mgcp-pat 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 !--- Configuration of TACACS+ server on the inside interface with server !--- tag name as mytacacs aaa-server mytacacs protocol tacacs+ aaa-server mytacacs (inside) host 10.10.10.100 key123 timeout 5 !--- Configuration of group-policy for VPN Clients. group-policy clientgroup internal group-policy clientgroup attributes vpn-idle-timeout 20 !--- See Note 2. !--- Enable and bind split-tunnel parameters to the group-policy. split-tunnel-policy tunnelspecified split-tunnel-network-list value splittunnel no snmp-server location no snmp-server contact snmp-server community public snmp-server enable traps snmp !--- Configuration of IPsec Phase 2. crypto ipsec transform-set myset esp-3des esp-sha-hmac !--- Crypto map configuration for VPN Clients that connect to this PIX. crypto dynamic-map rtpdynmap 20 set transform-set myset !--- Crypto map configuration for a static LAN-to-LAN tunnel. crypto map mymap 10 match address 100 crypto map mymap 10 set peer 172.20.77.10 crypto map mymap 10 set transform-set myset !--- Binding the dynamic map to the crypto map process. crypto map mymap 20 ipsec-isakmp dynamic rtpdynmap !--- Crypto map applied to the outside interface. crypto map mymap interface outside isakmp identity address isakmp enable outside !--- Configuration of Internet Security Association and Key Management !--- Protocol (ISAKMP) policy. isakmp policy 10 authentication pre-share isakmp policy 10 encryption 3des isakmp policy 10 hash md5 isakmp policy 10 group 2 isakmp policy 10 lifetime 86400 isakmp policy 65535 authentication pre-share isakmp policy 65535 encryption 3des isakmp policy 65535 hash sha isakmp policy 65535 group 2 isakmp policy 65535 lifetime 86400 isakmp disconnect-notify telnet timeout 5 ssh 0.0.0.0 0.0.0.0 outside ssh timeout 60 ssh version 1 console timeout 0 tunnel-group DefaultRAGroup type ipsec-ra tunnel-group DefaultRAGroup general-attributes authentication-server-group none tunnel-group DefaultRAGroup ipsec-attributes pre-shared-key * !--- Configuration of tunnel-group for the static LAN-to-LAN tunnel. !--- See the second note in the Configure section !--- of this document in order to configure tunnel-group. !--- The tunnel group name must be the IP address of the remote peer. tunnel-group 172.20.77.10 type ipsec-l2l tunnel-group 172.20.77.10 ipsec-attributes !--- Configuraiton of a pre-shared key for the static LAN-to-LAN tunnel. pre-shared-key * !--- Configuration of tunnel-group with group information for VPN Clients. tunnel-group rtptacvpn type ipsec-ra !--- Configuration of group parameters for the VPN Clients. tunnel-group rtptacvpn general-attributes address-pool vpnpool !--- Enable user authentication. authentication-server-group mytacacs authorization-server-group LOCAL !--- Bind group-policy parameters to the tunnel-group for VPN Clients. default-group-policy clientgroup tunnel-group rtptacvpn ipsec-attributes pre-shared-key * ! class-map inspection_default match default-inspection-traffic ! ! policy-map global_policy class inspection_default inspect dns maximum-length 512 inspect ftp inspect h323 h225 inspect h323 ras inspect http 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 Cryptochecksum:646541da0da9a4c764effd2e05633018 : end |
Note 1: The sysopt connection
permit-ipsec command must be configured to permit all inbound
IPsec authenticated cipher sessions. In PIX 7.0, the
sysopt commands do not show up in the running
configuration. In order to verify if the sysopt connection
permit-ipsec command is enabled, execute the show
running-config sysopt command.
Note 2: In order for VPN Clients to connect
through IPsec over User Data Protocol (UDP), configure this output in the
group-policy section of the PIX Appliance.
group-policy clientgroup attributes vpn-idle-timeout 20 ipsec-udp enable ipsec-udp-port 10000 split-tunnel-policy tunnelspecified split-tunnel-network-list value splittunnelNote 3: In order for VPN Clients to connect through IPsec over TCP, configure this command in the global configuration of the PIX Appliance. isakmp ipsec-over-tcp port 10000 |
| PIX3 |
|---|
PIX Version 6.3(4) interface ethernet0 auto interface ethernet1 auto interface ethernet2 auto shutdown interface ethernet3 auto shutdown interface ethernet4 auto shutdown interface ethernet5 auto shutdown nameif ethernet0 outside security0 nameif ethernet1 inside security100 nameif ethernet2 intf2 security4 nameif ethernet3 intf3 security6 nameif ethernet4 intf4 security8 nameif ethernet5 intf5 security10 enable password 8Ry2YjIyt7RRXU24 encrypted passwd 2KFQnbNIdI.2KYOU encrypted hostname PIX3 domain-name cisco.com 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 !--- Access-list for the encryption of traffic !--- between PIX3 and PIX1 networks. access-list 100 permit ip 10.11.10.0 255.255.255.0 10.10.10.0 255.255.255.0 !--- Access-list for the encryption of traffic !--- between the PIX3 network and the VPN Client address pool. access-list 100 permit ip |
VPN Client Configuration
Complete these steps in order to create a new connection entry on the VPN Client.
-
Enter the host IP address (PIX1 external IP address).
-
Under the Authentication tab, enter the group attributes (group name and password as configured on the PIX Appliance).
-
Under the Transport tab, choose the method of tunneling which you want to use for the VPN Clients connection. In this configuration, Enable Transport Tunneling is disabled for straight IPsec connectivity.
-
Click Save in order to save the connection profile configured on the VPN Client.
TACACS+ Server
In order to configure the TACACS+ server, complete these steps:
-
Click Add Entry in order to add an entry for the PIX in the TACACS+ server database.
-
On the Add AAA Client page, enter the PIX information as shown in this image:
-
In the AAA Client Hostname field, enter a name for the PIX.
-
In the AAA Client IP Address field, enter 10.10.10.1.
-
In the Key field, enter key123 as the shared secret key.
-
From the Authenticate Using drop-down list, choose TACACS+ (Cisco IOS), and click Submit.
-
-
In the User field, enter the user name for the VPN user in the Cisco Secure database, and click Add/Edit.
In this example, the user name is cisco.
-
On the next page, enter and confirm the password for the user cisco.
In this example, the password is also cisco.
-
If you want to map the user account to a group, complete that step now. When you finish, click Submit.
Hairpinning or U-Turn
This feature is useful for VPN traffic that enters an interface but is then routed out of that same interface. For example, if you have a hub and spoke VPN network, where the security appliance is the hub, and the remote VPN networks are the spokes, traffic must go into the security appliance and then out again to the other spoke in order for one spoke to communicate with another spoke.
Use the same-security-traffic configuration to allow traffic to enter and exit the same interface.
securityappliance(config)# same-security-traffic permit intra-interface
Verify
This section provides information you can use in order to confirm 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—Displays all current IKE security associations (SAs) at a peer.
-
show crypto ipsec sa—Displays all current SAs.
In order to test communication between the two private networks between PIX3 and PIX1, initiate a ping from one of the private networks.
In this configuration:
-
For static LAN-to-LAN, a ping is sent from behind the PIX3 network (10.11.10.x) to the PIX1 network (10.10.10.x).
-
In order for the VPN Clients to access the networks behind PIX3, a security association must be built from the PIX3 to PIX1 for VPN Client networks.
| PIX1 Verification |
|---|
show crypto isakmp sa
Active SA: 2
Rekey SA: 0 (A tunnel will report 1 Active and 1 Rekey SA during rekey)
Total IKE SA: 2
1 IKE Peer: 172.18.173.77
Type : user Role : responder
Rekey : no State : AM_ACTIVE
2 IKE Peer: 172.20.77.10
Type : L2L Role : responder
Rekey : no State : MM_ACTIVE
PIX1(config)#show crypto ipsec sa
interface: outside
Crypto map tag: rtpdynmap, local addr: 172.18.124.170
!--- IPsec SA for the connection between VPN Clients and the PIX1 network.
local ident (addr/mask/prot/port): (0.0.0.0/0.0.0.0/0/0)
remote ident (addr/mask/prot/port): (192.168.10.1/255.255.255.255/0/0)
current_peer: 172.18.173.77
dynamic allocated peer ip: 192.168.10.1
#pkts encaps: 12, #pkts encrypt: 12, #pkts digest: 12
#pkts decaps: 12, #pkts decrypt: 12, #pkts verify: 12
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 12, #pkts comp failed: 0, #pkts decomp failed: 0
#send errors: 0, #recv errors: 0
local crypto endpt.: 172.18.124.170, remote crypto endpt.: 172.18.173.77
path mtu 1500, ipsec overhead 60, media mtu 1500
current outbound spi: 1ECCB41D
inbound esp sas:
spi: 0x6C1615A7 (1813386663)
transform: esp-3des esp-sha-hmac
in use settings ={RA, Tunnel, }
slot: 0, conn_id: 5, crypto-map: rtpdynmap
sa timing: remaining key lifetime (sec): 28761
IV size: 8 bytes
replay detection support: Y
outbound esp sas:
spi: 0x1ECCB41D (516731933)
transform: esp-3des esp-sha-hmac
in use settings ={RA, Tunnel, }
slot: 0, conn_id: 5, crypto-map: rtpdynmap
sa timing: remaining key lifetime (sec): 28760
IV size: 8 bytes
replay detection support: Y
Crypto map tag: mymap, local addr: 172.18.124.170
!--- IPsec SA for connection between the VPN Clients network and PIX3 network.
local ident (addr/mask/prot/port): (192.168.10.0/255.255.255.0/0/0)
remote ident (addr/mask/prot/port): (10.11.10.0/255.255.255.0/0/0)
current_peer: 172.20.77.10
#pkts encaps: 8, #pkts encrypt: 8, #pkts digest: 8
#pkts decaps: 8, #pkts decrypt: 8, #pkts verify: 8
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 8, #pkts comp failed: 0, #pkts decomp failed: 0
#send errors: 0, #recv errors: 0
local crypto endpt.: 172.18.124.170, remote crypto endpt.: 172.20.77.10
path mtu 1500, ipsec overhead 60, media mtu 1500
current outbound spi: 9EF2885C
inbound esp sas:
spi: 0x82E9BF07 (2196356871)
transform: esp-3des esp-sha-hmac
in use settings ={L2L, Tunnel, }
slot: 0, conn_id: 4, crypto-map: mymap
sa timing: remaining key lifetime (kB/sec): (4274999/28786)
IV size: 8 bytes
replay detection support: Y
outbound esp sas:
spi: 0x9EF2885C (2666694748)
transform: esp-3des esp-sha-hmac
in use settings ={L2L, Tunnel, }
slot: 0, conn_id: 4, crypto-map: mymap
sa timing: remaining key lifetime (kB/sec): (4274999/28786)
IV size: 8 bytes
replay detection support: Y
Crypto map tag: mymap, local addr: 172.18.124.170
!--- IPsec security association for a connection between
!--- the PIX1 and PIX3 networks.
local ident (addr/mask/prot/port): (10.10.10.0/255.255.255.0/0/0)
remote ident (addr/mask/prot/port): (10.11.10.0/255.255.255.0/0/0)
current_peer: 172.20.77.10
#pkts encaps: 4, #pkts encrypt: 4, #pkts digest: 4
#pkts decaps: 4, #pkts decrypt: 4, #pkts verify: 4
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 4, #pkts comp failed: 0, #pkts decomp failed: 0
#send errors: 0, #recv errors: 0
local crypto endpt.: 172.18.124.170, remote crypto endpt.: 172.20.77.10
path mtu 1500, ipsec overhead 60, media mtu 1500
current outbound spi: C86585AB
inbound esp sas:
spi: 0x95604966 (2506115430)
transform: esp-3des esp-sha-hmac
in use settings ={L2L, Tunnel, }
slot: 0, conn_id: 4, crypto-map: mymap
sa timing: remaining key lifetime (kB/sec): (4274999/28653)
IV size: 8 bytes
replay detection support: Y
outbound esp sas:
spi: 0xC86585AB (3362096555)
transform: esp-3des esp-sha-hmac
in use settings ={L2L, Tunnel, }
slot: 0, conn_id: 4, crypto-map: mymap
sa timing: remaining key lifetime (kB/sec): (4274999/28652)
IV size: 8 bytes
replay detection support: Y
|
| PIX3 Verification |
|---|
PIX3(config)#show crypto isakmp sa
Total : 1
Embryonic : 0
dst src state pending created
172.18.124.170 172.20.77.10 QM_IDLE 0 2
PIX3(config)#show crypto ipsec sa
interface: outside
Crypto map tag: mymap, local addr. 172.20.77.10
!--- IPsec security association for a connection between
!--- the PIX3 and PIX1 networks.
local ident (addr/mask/prot/port): (10.11.10.0/255.255.255.0/0/0)
remote ident (addr/mask/prot/port): (10.10.10.0/255.255.255.0/0/0)
current_peer: 172.18.124.170:500
PERMIT, flags={origin_is_acl,}
#pkts encaps: 4, #pkts encrypt: 4, #pkts digest 4
#pkts decaps: 4, #pkts decrypt: 4, #pkts verify 4
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 0, #pkts compr. failed: 0, #pkts decompress failed: 0
#send errors 1, #recv errors 0
local crypto endpt.: 172.20.77.10, remote crypto endpt.: 172.18.124.170
path mtu 1500, ipsec overhead 56, media mtu 1500
current outbound spi: 95604966
inbound esp sas:
spi: 0xc86585ab(3362096555)
transform: esp-3des esp-sha-hmac ,
in use settings ={Tunnel, }
slot: 0, conn id: 4, crypto map: mymap
sa timing: remaining key lifetime (k/sec): (4607999/28213)
IV size: 8 bytes
replay detection support: Y
inbound ah sas:
inbound pcp sas:
outbound esp sas:
spi: 0x95604966(2506115430)
transform: esp-3des esp-sha-hmac ,
in use settings ={Tunnel, }
slot: 0, conn id: 3, crypto map: mymap
sa timing: remaining key lifetime (k/sec): (4607999/28213)
IV size: 8 bytes
replay detection support: Y
outbound ah sas:
outbound pcp sas:
!--- IPsec security association for the connection between the VPN Client
!--- network and PIX3 networks.
local ident (addr/mask/prot/port): (10.11.10.0/255.255.255.0/0/0)
remote ident (addr/mask/prot/port): (192.168.10.0/255.255.255.0/0/0)
current_peer: 172.18.124.170:500
PERMIT, flags={origin_is_acl,}
#pkts encaps: 8, #pkts encrypt: 8, #pkts digest 8
#pkts decaps: 8, #pkts decrypt: 8, #pkts verify 8
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 0, #pkts compr. failed: 0, #pkts decompress failed: 0
#send errors 1, #recv errors 0
local crypto endpt.: 172.20.77.10, remote crypto endpt.: 172.18.124.170
path mtu 1500, ipsec overhead 56, media mtu 1500
current outbound spi: 82e9bf07
inbound esp sas:
spi: 0x9ef2885c(2666694748)
transform: esp-3des esp-sha-hmac ,
in use settings ={Tunnel, }
slot: 0, conn id: 2, crypto map: mymap
sa timing: remaining key lifetime (k/sec): (4607999/28295)
IV size: 8 bytes
replay detection support: Y
inbound ah sas:
inbound pcp sas:
outbound esp sas:
spi: 0x82e9bf07(2196356871)
transform: esp-3des esp-sha-hmac ,
in use settings ={Tunnel, }
slot: 0, conn id: 1, crypto map: mymap
sa timing: remaining key lifetime (k/sec): (4607999/28295)
IV size: 8 bytes
replay detection support: Y
outbound ah sas:
outbound pcp sas:
|
VPN Client Verification
Complete these steps in order to verify the VPN Client:
-
Right-click on the VPN Client lock icon present at the system tray after successful connection and choose the option for statistics.
You can view details about the VPN Client connection and encryption and decryption of packet information.
-
Click on the Route Details tab in order to verify the split-tunnel list passed down from the PIX Security Appliance.
Troubleshoot
This section provides information you can use in order 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.
-
clear crypto isakmp sa—Clears the phase 1 security associations (SAs).
-
clear crypto ipsec sa—Clears the phase 2 SAs
-
debug crypto isakmp sa—Debugs ISAKMP SA negotiations.
-
debug crypto ipsec sa—Debugs IPsec SA negotiations.
Related Information
Open a Support Case 
(Requires a Cisco Service Contract.)
Related Cisco Support Community Discussions
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Refer to Cisco Technical Tips Conventions for information on conventions used in this document.