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IPsec virtual tunnel interfaces (VTIs) provide a routable interface type for terminating IPsec tunnels and an easy way to define protection between sites to form an overlay network. IPsec VTIs simplify the configuration of IPsec for protection of remote links, support multicast, and simplify network management and load balancing.
Note |
Security threats, as well as the cryptographic technologies to help protect against them, are constantly changing. For more information about the latest Cisco cryptographic recommendations, see the Next Generation Encryption (NGE) white paper. |
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
The IPsec transform set must be configured in tunnel mode only.
The Internet Key Exchange (IKE) security association (SA) is bound to the VTI. Therefore, the same IKE SA cannot be used for a crypto map.
Static VTIs (SVTIs) support only a single IPsec SA that is attached to the VTI interface. The traffic selector for the IPsec SA is always "IP any any."
A dynamic VTI (DVTIs) is also a point-to-point interface that can support multiple IPsec SAs. The DVTI can accept the multiple IPsec selectors that are proposed by the initiator.
This feature supports SVTIs that are configured to encapsulate IPv4 packets or IPv6 packets, but IPv4 packets cannot carry IPv6 packets and IPv6 packets cannot carry IPv4 packets.
SVTIs support only the "IP any any" proxy.
DVTIs support multiple proxies, but DVTIs do not allow mixing "any any" proxies with non-"any any" proxies. DVTIs permit only one type of proxy at a time, either a single "any any" proxy or multiple "no any any" proxies.
The shaped traffic is process switched.
IPsec stateful failover is not supported with IPsec VTIs.
The IPsec VTI is limited to the IP unicast and multicast traffic only, as opposed to Generic Routing Encapsulation (GRE) tunnels, which have a wider application for IPsec implementation.
In the single template model, the VPN routing and forwarding (VRF) is configured in the ISAKMP profile. In this model, each virtual access that is created belongs to the internal VRF (IVRF) specified in the ISAKMP profile. But because the IP address of the virtual access is derived from the interface to which the virtual access is unnumbered to, the IP address of the interface will not be available in the virtual access routing table. This happens because the unnumbered interface does not belong to the IVRF routing table of the virtual access. In such cases, a ping to the virtual access IP address fails.
Do not configure the shared keyword when using the tunnel mode ipsec ipv4 command for IPsec IPv4 mode.
Effective with CSCtt26236, the virtual template lock allows you to modify or delete a virtual template of type tunnel only when the virtual template is not associated with any cloned virtual access interfaces. The virtual template lock prevents dynamic command updates from virtual templates to the cloned virtual access interfaces, which can cause instability in some scenarios.
If you try to modify or delete an active virtual template of type tunnel, the following error message appears:
Device(config)# interface virtual-template 1
% Virtual-template config is locked, active vaccess present
Although the virtual template cannot be modified when the virtual template is associated with a virtual access interface, perform the following steps to modify an existing virtual template configuration:
The new session will use the new virtual template.
VPN routing and forwarding (VRF) must not be configured in the Internet Security Association and Key Management Protocol (ISAKMP) profile in VRF-aware IPsec configurations with either SVTIs or DVTIs. Instead, the VRF must be configured on the tunnel interface for SVTIs. For DVTIs, you must apply the VRF to the virtual template using the ip vrf forwarding command.
The use of IPsec VTIs both greatly simplifies the configuration process when you need to provide protection for remote access and provides a simpler alternative to using generic routing encapsulation (GRE) or Layer 2 Tunneling Protocol (L2TP) tunnels for encapsulation and crypto maps with IPsec. A major benefit associated with IPsec VTIs is that the configuration does not require a static mapping of IPsec sessions to a physical interface. The IPsec tunnel endpoint is associated with an actual (virtual) interface. Because there is a routable interface at the tunnel endpoint, many common interface capabilities can be applied to the IPsec tunnel.
The IPsec VTI allows for the flexibility of sending and receiving both IP unicast and multicast encrypted traffic on any physical interface, such as in the case of multiple paths. Traffic is encrypted or decrypted when it is forwarded from or to the tunnel interface and is managed by the IP routing table. Using IP routing to forward the traffic to the tunnel interface simplifies the IPsec VPN configuration compared to the more complex process of using access control lists (ACLs) with the crypto map in native IPsec configurations. Because DVTIs function like any other real interface you can apply quality of service (QoS), firewall, and other security services as soon as the tunnel is active.
Without VPN Acceleration Module2+ (VAM2+) accelerating virtual interfaces, the packet traversing an IPsec virtual interface is directed to the Router Processor (RP) for encapsulation. This method tends to be slow and has limited scalability. In hardware crypto mode, all the IPsec VTIs are accelerated by the VAM2+ crypto engine, and all traffic going through the tunnel is encrypted and decrypted by the VAM2+.
The following sections provide details about the IPsec VTI:
IPsec VTIs allow you to configure a virtual interface to which you can apply features. Features for clear-text packets are configured on the VTI. Features for encrypted packets are applied on the physical outside interface. When IPsec VTIs are used, you can separate the application of features such as Network Address Translation (NAT), ACLs, and QoS and apply them to clear-text, or encrypted text, or both. When crypto maps are used, there is no simple way to apply extra features to the IPsec tunnel.
There are two types of VTI interfaces: static VTIs (SVTIs) and dynamic VTIs (DVTIs).
SVTI configurations can be used for site-to-site connectivity in which a tunnel provides always-on access between two sites. The advantage of using SVTIs as opposed to crypto map configurations is that users can enable dynamic routing protocols on the tunnel interface without the extra 24 bytes required for GRE headers, thus reducing the bandwidth for sending encrypted data.
Additionally, multiple Cisco IOS software features can be configured directly on the tunnel interface and on the physical egress interface of the tunnel interface. This direct configuration allows users to have solid control on the application of the features in the pre- or post-encryption path.
The figure below illustrates how a SVTI is used.
Figure 1 | IPsec SVTI |
The IPsec VTI supports native IPsec tunneling and exhibits most of the properties of a physical interface.
Note |
When configuring IPsec SVTI with high availability (HA), the standby router reload does not affect the existing security associations. |
DVTIs can provide highly secure and scalable connectivity for remote-access VPNs. The DVTI technology replaces dynamic crypto maps and the dynamic hub-and-spoke method for establishing tunnels.
DVTIs can be used for both the server and the remote configuration. The tunnels provide an on-demand separate virtual access interface for each VPN session. The configuration of the virtual access interfaces is cloned from a virtual template configuration, which includes the IPsec configuration and any Cisco IOS software feature configured on the virtual template interface, such as QoS, NetFlow, or ACLs.
DVTIs function like any other real interface, so you can apply QoS, firewall, or other security services as soon as the tunnel is active. QoS features can be used to improve the performance of various applications across the network. Any combination of QoS features offered in Cisco IOS software can be used to support voice, video, or data applications.
DVTIs provide efficiency in the use of IP addresses and provide secure connectivity. DVTIs allow dynamically downloadable per-group and per-user policies to be configured on a RADIUS server. The per-group or per-user definition can be created using an extended authentication (Xauth) User or Unity group, or can be derived from a certificate. DVTIs are standards based, so interoperability in a multiple-vendor environment is supported. IPsec DVTIs allow you to create highly secure connectivity for remote access VPNs and can be combined with Cisco Architecture for Voice, Video, and Integrated Data (AVVID) to deliver converged voice, video, and data over IP networks. The DVTI simplifies VPN routing and forwarding- (VRF-) aware IPsec deployment. The VRF is configured on the interface.
A DVTI requires minimal configuration on the router. A single virtual template can be configured and cloned.
The DVTI creates an interface for IPsec sessions and uses the virtual template infrastructure for dynamic instantiation and management of dynamic IPsec VTIs. The virtual template infrastructure is extended to create dynamic virtual-access tunnel interfaces. DVTIs are used in hub-and-spoke configurations. A single DVTI can support several static VTIs.
Note |
DVTI is supported only in Easy VPNs. That is, the DVTI end must be configured as an Easy VPN server. |
The figure below illustrates the DVTI authentication path.
Figure 2 | Dynamic IPsec VTI |
The authentication shown in the figure above follows this path:
IPsec profiles define the policy for DVTIs. The dynamic interface is created at the end of IKE Phase 1 and IKE Phase 1.5. The interface is deleted when the IPsec session to the peer is closed. The IPsec session is closed when both IKE and IPsec SAs to the peer are deleted.
Because VTIs are routable interfaces, routing plays an important role in the encryption process. Traffic is encrypted only if it is forwarded out of the VTI, and traffic arriving on the VTI is decrypted and routed accordingly. VTIs allow you to establish an encryption tunnel using a real interface as the tunnel endpoint. You can route to the interface or apply services such as QoS, firewalls, network address translation (NAT), and NetFlow statistics as you would to any other interface. You can monitor the interface and route to it, and the interface has an advantage over crypto maps because it is a real interface and provides benefits similar to other Cisco IOS interface.
When an IPsec VTI is configured, encryption occurs in the tunnel. Traffic is encrypted when it is forwarded to the tunnel interface. Traffic forwarding is handled by the IP routing table, and dynamic or static routing can be used to route traffic to the SVTI. DVTI uses reverse route injection to further simplify the routing configurations. Using IP routing to forward the traffic to encryption simplifies the IPsec VPN configuration because the use of ACLs with a crypto map in native IPsec configurations is not required. The IPsec virtual tunnel also allows you to encrypt multicast traffic with IPsec.
IPsec packet flow into the IPsec tunnel is illustrated in the figure below.
Figure 3 | Packet Flow into the IPsec Tunnel |
After packets arrive on the inside interface, the forwarding engine switches the packets to the VTI, where they are encrypted. The encrypted packets are handed back to the forwarding engine, where they are switched through the outside interface.
The figure below shows the packet flow out of the IPsec tunnel.
Figure 4 | Packet Flow out of the IPsec Tunnel |
Command or Action | Purpose | |
---|---|---|
|
Example: Device> enable |
Enables privileged Exec mode. Enter your password if prompted. |
|
Example: Device# configure terminal |
Enables global configuration mode. |
|
Example: Device(config)# crypto keyring KR-FVRF |
Defines the crypto keyring name to which the keyring will be referenced. |
|
Example: Device(config)# crypto keyring vrf FVRF |
Defines the crypto keyring name for a virtual routing and forwarding (VRF) instance to which the keyring will be referenced. |
|
Example: Device(config-keyring)# pre-shared-key address 10.0.0.2 |
Defines the preshared key IP address of the remote host. |
|
Example: Device(config-keyring)# pre-shared-key address 10.0.0.2 key cisco |
Defines the secret key for the preshared key IP address of the remote host. |
|
Example: Device(config-keyring)# exit |
Exits keyring configuration mode, and enters global configuration mode. |
|
Example: Device(config)# interface tunnel 0 |
Specifies the interface on which the tunnel will be configured and enters interface configuration mode. |
|
Example: Device(config-if)# ip vrf forwarding IVRF |
Specifies the virtual routing and forwarding (VRF) name for the interface. |
|
Example: Device(config-if)# ip address 10.0.0.1 255.255.255.0 |
Specifies the IP address and address mask. |
|
Example: Device(config-if)# tunnel source 10.0.0.1 |
Specifies the IP address of the tunnel source. |
|
Example: Device(config-if)# tunnel destination 10.0.0.2 |
Specifies the IP address of the tunnel destination. |
|
Example: Device(config-if)# tunnel mode ipsec ipv4 |
Defines the mode for the tunnel. |
|
Example: Device(config-if)# tunnel vrf FVRF |
Defines the virtual routing and forwarding (VRF) instance for the tunnel. |
|
Example: Device(config-if)# tunnel protection IPsec profile IPSec-Profile |
Associates a tunnel interface with an IPsec profile. |
|
Example: Device(config-if)# exit |
Exits interface configuration mode, and enters global configuration mode. |
|
Example: Device(config)# interface FastEthernet0/0 |
Specifies the interface type. |
|
Example: Device(config-if)# ip vrf forwarding FVRF |
Specifies the VRF forwarding table for the interface. |
|
Example: Device(config-if)# ip address 10.0.0.1 255.255.255.0 |
Specifies the IP address and address mask. |
|
Example: Device(config-if)# no shutdown |
Enables the interface (brings it up). |
|
Example: Device(config-if)# end |
Exits interface configuration mode and returns to privileged EXEC mode. |
The following example configuration uses a preshared key for authentication between peers. VPN traffic is forwarded to the IPsec VTI for encryption and then sent out the physical interface. The tunnel on subnet 10 checks packets for the IPsec policy and passes them to the Crypto Engine (CE) for IPsec encapsulation. The figure below illustrates the IPsec VTI configuration.
Figure 5 | VTI with IPsec |
version 12.3 service timestamps debug datetime service timestamps log datetime hostname 7200-3 no aaa new-model ip subnet-zero ip cef controller ISA 6/1 ! crypto isakmp policy 1 encr aes authentication pre-share group 14 crypto isakmp key Cisco12345 address 0.0.0.0 0.0.0.0 crypto ipsec transform-set T1 esp-aes esp-sha-hmac crypto ipsec profile P1 set transform-set T1 ! interface Tunnel0 ip address 10.0.51.203 255.255.255.0 ip ospf mtu-ignore load-interval 30 tunnel source 10.0.149.203 tunnel destination 10.0.149.217 tunnel mode IPsec ipv4 tunnel protection IPsec profile P1 ! interface Ethernet3/0 ip address 10.0.149.203 255.255.255.0 duplex full ! interface Ethernet3/3 ip address 10.0.35.203 255.255.255.0 duplex full ! ip classless ip route 10.0.36.0 255.255.255.0 Tunnel0 line con 0 line aux 0 line vty 0 4 end
version 12.3 hostname c1750-17 no aaa new-model ip subnet-zero ip cef crypto isakmp policy 1 encr aes authentication pre-share group 14 crypto isakmp key Cisco12345 address 0.0.0.0 0.0.0.0 crypto ipsec transform-set T1 esp-aes esp-sha-hmac crypto ipsec profile P1 set transform-set T1 ! interface Tunnel0 ip address 10.0.51.217 255.255.255.0 ip ospf mtu-ignore tunnel source 10.0.149.217 tunnel destination 10.0.149.203 tunnel mode ipsec ipv4 tunnel protection ipsec profile P1 ! interface FastEthernet0/0 ip address 10.0.149.217 255.255.255.0 speed 100 full-duplex ! interface Ethernet1/0 ip address 10.0.36.217 255.255.255.0 load-interval 30 full-duplex ! ip classless ip route 10.0.35.0 255.255.255.0 Tunnel0 line con 0 line aux 0 line vty 0 4 end
This section provides information that you can use to confirm that your configuration is working properly. In this display, Tunnel 0 is "up," and the line protocol is "up." If the line protocol is "down," the session is not active.
Router# show interface tunnel 0 Tunnel0 is up, line protocol is up Hardware is Tunnel Internet address is 10.0.51.203/24 MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec, reliability 255/255, txload 103/255, rxload 110/255 Encapsulation TUNNEL, loopback not set Keepalive not set Tunnel source 10.0.149.203, destination 10.0.149.217 Tunnel protocol/transport ipsec/ip, key disabled, sequencing disabled Tunnel TTL 255 Checksumming of packets disabled, fast tunneling enabled Tunnel transmit bandwidth 8000 (kbps) Tunnel receive bandwidth 8000 (kbps) Tunnel protection via IPsec (profile "P1") Last input never, output never, output hang never Last clearing of "show interface" counters never Input queue: 1/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/0 (size/max) 30 second input rate 13000 bits/sec, 34 packets/sec 30 second output rate 36000 bits/sec, 34 packets/sec 191320 packets input, 30129126 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 59968 packets output, 15369696 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 output buffer failures, 0 output buffers swapped out Router# show crypto session Crypto session current status Interface: Tunnel0 Session status: UP-ACTIVE Peer: 10.0.149.217 port 500 IKE SA: local 10.0.149.203/500 remote 10.0.149.217/500 Active IPsec FLOW: permit ip 0.0.0.0/0.0.0.0 0.0.0.0/0.0.0.0 Active SAs: 4, origin: crypto map Router# show ip route Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route Gateway of last resort is not set 10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks C 10.0.35.0/24 is directly connected, Ethernet3/3 S 10.0.36.0/24 is directly connected, Tunnel0 C 10.0.51.0/24 is directly connected, Tunnel0 C 10.0.149.0/24 is directly connected, Ethernet3/0
To add the VRF to the static VTI example, include the ipvrf and ip vrf forwarding commands to the configuration as shown in the following example.
hostname cisco 7206 . . ip vrf sample-vti1 rd 1:1 route-target export 1:1 route-target import 1:1 ! . . interface Tunnel0 ip vrf forwarding sample-vti1 ip address 10.0.51.217 255.255.255.0 tunnel source 10.0.149.217 tunnel destination 10.0.149.203 tunnel mode ipsec ipv4 tunnel protection ipsec profile P1 . . ! end
You can apply any QoS policy to the tunnel endpoint by including the service-policy statement under the tunnel interface. The following example shows how to police traffic out the tunnel interface.
hostname cisco 7206 . . class-map match-all VTI match any ! policy-map VTI class VTI police cir 2000000 conform-action transmit exceed-action drop ! . . interface Tunnel0 ip address 10.0.51.217 255.255.255.0 tunnel source 10.0.149.217 tunnel destination 10.0.149.203 tunnel mode ipsec ipv4 tunnel protection ipsec profile P1 service-policy output VTI ! . . ! end
Applying the virtual firewall to the SVTI tunnel allows traffic from the spoke to pass through the hub to reach the Internet. The figure below illustrates an SVTI with the spoke protected inherently by the corporate firewall.
Figure 6 | Static VTI with Virtual Firewall |
The basic SVTI configuration has been modified to include the virtual firewall definition:
hostname cisco 7206 . . ip inspect max-incomplete high 1000000 ip inspect max-incomplete low 800000 ip inspect one-minute high 1000000 ip inspect one-minute low 800000 ip inspect tcp synwait-time 60 ip inspect tcp max-incomplete host 100000 block-time 2 ip inspect name IOSFW1 tcp timeout 300 ip inspect name IOSFW1 udp ! . . interface GigabitEthernet0/1 description Internet Connection ip address 172.18.143.246 255.255.255.0 ip access-group 100 in ip nat outside ! interface Tunnel0 ip address 10.0.51.217 255.255.255.0 ip nat inside ip inspect IOSFW1 in tunnel source 10.0.149.217 tunnel destination 10.0.149.203 tunnel mode ipsec ipv4 tunnel protection ipsec profile P1 ! ip classless ip route 0.0.0.0 0.0.0.0 172.18.143.1 ! ip nat translation timeout 120 ip nat translation finrst-timeout 2 ip nat translation max-entries 300000 ip nat pool test1 10.2.100.1 10.2.100.50 netmask 255.255.255.0 ip nat inside source list 110 pool test1 vrf test-vti1 overload ! access-list 100 permit esp any any access-list 100 permit udp any eq isakmp any access-list 100 permit udp any eq non500-isakmp any access-list 100 permit icmp any any access-list 110 deny esp any any access-list 110 deny udp any eq isakmp any access-list 110 permit ip any any access-list 110 deny udp any eq non500-isakmp any ! end
The following example illustrates the use of the DVTI Easy VPN server, which serves as an IPsec remote access aggregator. The client can be a home user running a Cisco VPN client or a Cisco IOS router configured as an Easy VPN client.
hostname cisco 7206 ! aaa new-model aaa authentication login local_list local aaa authorization network local_list local aaa session-id common ! ip subnet-zero ip cef ! username cisco password 0 cisco123 ! controller ISA 1/1 ! crypto isakmp policy 1 encr aes authentication pre-share group 14 ! crypto isakmp client configuration group group1 key cisco123 pool group1pool save-password ! crypto isakmp profile vpn1-ra match identity group group1 client authentication list local_list isakmp authorization list local_list client configuration address respond virtual-template 1 ! crypto ipsec transform-set VTI-TS esp-aes esp-sha-hmac ! crypto ipsec profile test-vti1 set transform-set VTI-TS ! interface GigabitEthernet0/1 description Internet Connection ip address 172.18.143.246 255.255.255.0 ! interface GigabitEthernet0/2 description Internal Network ip address 10.2.1.1 255.255.255.0 ! interface Virtual-Template1 type tunnel ip unnumbered GigabitEthernet0/1 ip virtual-reassembly tunnel mode ipsec ipv4 tunnel protection ipsec profile test-vti1 ! ip local pool group1pool 192.168.1.1 192.168.1.4 ip classless ip route 0.0.0.0 0.0.0.0 172.18.143.1 ! end
The following examples show that a DVTI has been configured for an Easy VPN server.
Router# show running-config interface Virtual-Access2 Building configuration... Current configuration : 250 bytes ! interface Virtual-Access2 ip unnumbered GigabitEthernet0/1 ip virtual-reassembly tunnel source 172.18.143.246 tunnel destination 172.18.143.208 tunnel mode ipsec ipv4 tunnel protection ipsec profile test-vti1 no tunnel protection ipsec initiate end Router# show ip route Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route Gateway of last resort is 10.2.1.10 to network 0.0.0.0 172.18.0.0/24 is subnetted, 1 subnets C 172.18.143.0 is directly connected, GigabitEthernet0/1 192.168.1.0/32 is subnetted, 1 subnets S 192.168.1.1 [1/0] via 0.0.0.0, Virtual-Access2 10.0.0.0/24 is subnetted, 1 subnets C 10.2.1.0 is directly connected, GigabitEthernet0/2 S* 0.0.0.0/0 [1/0] via 172.18.143.1
The following example shows how you can set up a router as the Easy VPN client. This example uses the same idea as the Easy VPN client that you can run from a PC to connect to a network. The configuration of the Easy VPN server will work for the software client or the Cisco IOS client.
hostname cisco 1841 ! no aaa new-model ! ip cef ! username cisco password 0 cisco123 ! crypto ipsec client ezvpn CLIENT connect manual group group1 key cisco123 mode client peer 172.18.143.246 virtual-interface 1 username cisco password cisco123 xauth userid mode local ! interface Loopback0 ip address 10.1.1.1 255.255.255.255 ! interface FastEthernet0/0 description Internet Connection ip address 172.18.143.208 255.255.255.0 crypto ipsec client ezvpn CLIENT ! interface FastEthernet0/1 ip address 10.1.1.252 255.255.255.0 crypto ipsec client ezvpn CLIENT inside ! interface Virtual-Template1 type tunnel ip unnumbered Loopback0 ! ip route 0.0.0.0 0.0.0.0 172.18.143.1 254 ! end
The client definition can be set up in many different ways. The mode specified with the connect command can be automatic or manual. If the connect mode is set to manual, the IPsec tunnel has to be initiated manually by a user.
Note the use of the mode command. The mode can be a client, network-extension, or network-extension-plus. This example indicates the client mode, which means that the client is given a private address from the server. The network-extension mode is different from the client mode in that the client specifies for the server its attached private subnet. Depending on the mode, the routing table on either end will be slightly different. The basic operation of the IPsec tunnel remains the same, regardless of the specified mode.
The following examples illustrate different ways to display the status of the DVTI.
Router# show running-config interface Virtual-Access2 Building configuration... Current configuration : 148 bytes ! interface Virtual-Access2 ip unnumbered Loopback1 tunnel source FastEthernet0/0 tunnel destination 172.18.143.246 tunnel mode ipsec ipv4 end Router# show running-config interface Loopback1 Building configuration... Current configuration : 65 bytes ! interface Loopback1 ip address 192.168.1.1 255.255.255.255 end Router# show ip route Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route Gateway of last resort is 172.18.143.1 to network 0.0.0.0 10.0.0.0/32 is subnetted, 1 subnets C 10.1.1.1 is directly connected, Loopback0 172.18.0.0/24 is subnetted, 1 subnets C 172.18.143.0 is directly connected, FastEthernet0/0 192.168.1.0/32 is subnetted, 1 subnets C 192.168.1.1 is directly connected, Loopback1 S* 0.0.0.0/0 [1/0] via 0.0.0.0, Virtual-Access2 Router# show crypto ipsec client ezvpn Easy VPN Remote Phase: 6 Tunnel name : CLIENT Inside interface list: FastEthernet0/1 Outside interface: Virtual-Access2 (bound to FastEthernet0/0) Current State: IPSEC_ACTIVE Last Event: SOCKET_UP Address: 192.168.1.1 Mask: 255.255.255.255 Save Password: Allowed Current EzVPN Peer: 172.18.143.246
This example shows how to configure VRF-Aware IPsec to take advantage of the DVTI:
hostname c7206 . . ip vrf test-vti1 rd 1:1 route-target export 1:1 route-target import 1:1 ! . . interface Virtual-Template1 type tunnel ip vrf forwarding test-vti1 ip unnumbered Loopback0 ip virtual-reassembly tunnel mode ipsec ipv4 tunnel protection ipsec profile test-vti1 ! . . end
The DVTI Easy VPN server can be configured behind a virtual firewall. Behind-the-firewall configuration allows users to enter the network, while the network firewall is protected from unauthorized access. The virtual firewall uses Context-Based Access Control (CBAC) and NAT applied to the Internet interface as well as to the virtual template.
hostname cisco 7206 . . ip inspect max-incomplete high 1000000 ip inspect max-incomplete low 800000 ip inspect one-minute high 1000000 ip inspect one-minute low 800000 ip inspect tcp synwait-time 60 ip inspect tcp max-incomplete host 100000 block-time 2 ip inspect name IOSFW1 tcp timeout 300 ip inspect name IOSFW1 udp ! . . interface GigabitEthernet0/1 description Internet Connection ip address 172.18.143.246 255.255.255.0 ip access-group 100 in ip nat outside ! interface GigabitEthernet0/2 description Internal Network ip address 10.2.1.1 255.255.255.0 ! interface Virtual-Template1 type tunnel ip unnumbered Loopback0 ip nat inside ip inspect IOSFW1 in tunnel mode ipsec ipv4 tunnel protection ipsec profile test-vti1 ! ip classless ip route 0.0.0.0 0.0.0.0 172.18.143.1 ! ip nat translation timeout 120 ip nat translation finrst-timeout 2 ip nat translation max-entries 300000 ip nat pool test1 10.2.100.1 10.2.100.50 netmask 255.255.255.0 ip nat inside source list 110 pool test1 vrf test-vti1 overload ! access-list 100 permit esp any any access-list 100 permit udp any eq isakmp any access-list 100 permit udp any eq non500-isakmp any access-list 100 permit icmp any any access-list 110 deny esp any any access-list 110 deny udp any eq isakmp any access-list 110 permit ip any any access-list 110 deny udp any eq non500-isakmp any ! end
You can add QoS to the DVTI tunnel by applying the service policy to the virtual template. When the template is cloned to make the virtual access interface, the service policy will also be applied to the virtual access interface. The following example shows the basic DVTI configuration with QoS added.
hostname cisco 7206 . . class-map match-all VTI match any ! policy-map VTI class VTI police cir 2000000 conform-action transmit exceed-action drop ! . . interface Virtual-Template1 type tunnel ip vrf forwarding test-vti1 ip unnumbered Loopback0 ip virtual-reassembly tunnel mode ipsec ipv4 tunnel protection ipsec profile test-vti1 service-policy output VTI ! . . ! end
Standard/RFC |
Title |
---|---|
RFC 2401 |
Security Architecture for the Internet Protocol |
RFC 2408 |
Internet Security Association and Key Management Protocol |
RFC 2409 |
The Internet Key Exchange (IKE) |
Description |
Link |
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The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
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Table 1 | Feature Information for IPsec Virtual Tunnel Interfaces |
Feature Name |
Releases |
Feature Configuration Information |
---|---|---|
Dynamic IPsec VTIs |
12.3(7)T 12.3(14)T |
Dynamic VTIs enable efficient use of IP addresses and provide secure connectivity. Dynamic VTIs allow dynamically downloadable per-group and per-user policies to be configured on a RADIUS server. IPsec dynamic VTIs allow you to create highly secure connectivity for remote access VPNs. The dynamic VTI simplifies VRF-aware IPsec deployment. The following commands were introduced or modified: crypto isakmp profile, interface virtual-template, show vtemplate, tunnel mode, virtual-template. |
Multi-SA for Dynamic VTIs |
15.2(1)T |
The DVTI can accept multiple IPsec selectors that are proposed by the initiator. The following commands were introduced or modified: set security-policy limit, set reverse-route. |
Static IPsec VTIs |
12.2(33)SRA 12.2(33)SXH 12.3(7)T 12.3(14)T |
IPsec VTIs provide a routable interface type for terminating IPsec tunnels and an easy way to define protection between sites to form an overlay network. IPsec VTIs simplify configuration of IPsec for protection of remote links, support multicast, and simplify network management and load balancing. |
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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.