IPsec Virtual Tunnel Interfaces

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.

Finding Feature Information

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.

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.

Restrictions for IPsec Virtual Tunnel Interfaces

Fragmentation

Fragmentation is not supported over IPsec tunnel. You can choose to set the lower MTU on hosts to avoid packet fragments or choose to fragment the packets on any device before it reaches ASR 920.

IPsec Transform Set

The IPsec transform set must be configured in tunnel mode only.

IKE Security Association

The Internet Key Exchange (IKE) security association (SA) is bound to the VTI.

IPsec SA Traffic Selectors

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.”

IPv4

This feature supports SVTIs that are configured to encapsulate IPv4 packets .

Tunnel Protection

Do not configure the shared keyword when using the tunnel mode ipsec ipv4 command for IPsec IPv4 mode.

Traceroute

The traceroute function with crypto offload on VTIs is not supported.

Information About IPsec Virtual Tunnel Interfaces

The use of IPsec VTIs can simplify the configuration process when you need to provide protection for remote access and it provides an alternative to using generic routing encapsulation (GRE) or Layer 2 Tunneling Protocol (L2TP) tunnels for encapsulation. A benefit of using IPsec VTIs is that the configuration does not require 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 . 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.

The following sections provide details about the IPSec VTI:

Benefits of Using IPsec Virtual Tunnel Interfaces

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.

There are two types of VTI interfaces: static VTIs (SVTIs) and dynamic VTIs (DVTIs).

Static Virtual Tunnel Interfaces

SVTI configurations can be used for site-to-site connectivity in which a tunnel provides always-on access between two sites.

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.

Dynamic Virtual Tunnel Interfaces

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.


Note

You can configure DVTIs with IKEv1 or IKEv2. The legacy crypto map based configuration supports DVTIs with IKEv1 only. A DVTI configuration with IKEv2 is supported only in FlexVPN.

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.

The figure below illustrates the DVTI authentication path.

Figure 2. Dynamic IPsec VTI

The authentication shown in the figure above follows this path:

  1. User 1 calls the router.

  2. Router 1 authenticates User 1.

  3. IPsec clones the virtual access interface from the virtual template interface.

Traffic Encryption with the IPsec Virtual Tunnel 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 . 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

Multi-SA Support for Dynamic Virtual Interfaces

DVTI supports multiple IPsec SAs. The DVTI can accept multiple IPsec selectors that are proposed by the initiator.

The DVTIs allow per-peer features to be applied on a dedicated interface. You can order features in such way that all features that are applied on the virtual access interfaces are applied before applying crypto. Additionally, all the features that are applied on the physical interfaces are applied after applying crypto. Clean routing is available across all VRFs so that there are no traffic leaks from one VRF to another before encrypting.

Multi-SA VTIs ensure interoperation with third-party devices and provide a flexible, clean, and modular feature-set.

Multi-SA VTIs enable a clean Cisco IOS XE infrastructure, even when the Cisco IOS XE software interoperates with the third-party devices that only implement crypto maps.

VRF and Scalability of Baseline Configuration:

Virtual access instances inherit the Inside-VRF (IVRF) from the template configuration. Users must configure several templates to enforce an appropriate IVRF for each customer. The number of templates must be equal to the number of customers connecting to the headend. Such a configuration is cumbersome and undesirable and also affects performance because each template declaration consumes one Interface Descriptor Block (IDB).

This complication can be avoided by allowing the IKE profile to override the virtual access VRF with the VRF configured on the IKE profile. A better solution is to allow the IKE profile to override the virtual access VRF using AAA, but this method is supported only for IKEv2.

The VRF configured in the ISAKMP profile is applied to the virtual access first. Then the configuration from virtual template is applied to the virtual access. If your virtual template contains ip vrf forwarding command configuration, the VRF from the template overrides the VRF from the ISAKMP profile.

Rules for Initial Configuration of a VRF:

The following rules must be applied during the initial configuration of VRF:

  • If you configure IVRF in the IKE profile without configuring it in the virtual template, then you must apply the VRF from the IKE profile on each virtual access derived from this IKE profile.
  • If you configure VRF in an IKE profile and virtual template, then the virtual template IVRF gets precedence.

Rules for Changing the VRF:

If you change the VRF configured in an IKE profile, all the IKE SAs, IPsec SAs, and the virtual access identifier derived from this profile will get deleted. The same rule applies when the VRF is configured on the IKE profile for the first time.

Dynamic Virtual Tunnel Interface Life Cycle

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.

Routing with IPsec Virtual Tunnel Interfaces

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 provides benefits similar to other Cisco IOS interface.

FlexVPN Mixed Mode Support

The FlexVPN Mixed Mode feature provides support for carrying IPv4 traffic over IPsec IPv6 transport. This is the first phase towards providing dual stack support on the IPsec stack. This implementation does not support using a single IPsec security association (SA) pair for both IPv4 and IPv6 traffic.

This feature is only supported for Remote Access VPN with IKEv2 and Dynamic VTI.

The FlexVPN Mixed Mode feature provides support for carrying IPv6 traffic over IPsec IPv4 transport from Cisco IOS XE Everest 16.4.1.

Auto Tunnel Mode Support in IPsec

When configuring a VPN headend in a multiple vendor scenario, you must be aware of the technical details of the peer or responder. For example, some devices may use IPsec tunnels while others may use generic routing encapsulation (GRE) or IPsec tunnel, and sometimes, a tunnel may be IPv4 or IPv6. In the last case, you must configure an Internet Key Exchange (IKE) profile and a virtual template.

The Tunnel Mode Auto Selection feature eases the configuration and spares you about knowing the responder’s details. This feature automatically applies the tunneling protocol (GRE or IPsec) and transport protocol (IPv4 or IPv6) on the virtual template as soon as the IKE profile creates the virtual access interface. This feature is useful on dual stack hubs aggregating multivendor remote access, such as Cisco AnyConnect VPN Client, Microsoft Windows7 Client, and so on.


Note
The Tunnel Mode Auto Selection feature eases the configuration for a responder only. The tunnel must be statically configured for an initiator.

IPSec Mixed Mode Support for VTI

The IPSec Mixed Mode feature provides support for carrying IPv4 traffic over IPsec IPv6 transport. This is the first phase towards providing dual stack support on the IPsec stack. This implementation does not support using a single IPsec security association (SA) pair for both IPv4 and IPv6 traffic.

This feature is supported for SVTI as well as DVTI and IKEv1 as well as IKEv2.

How to Configure IPsec Virtual Tunnel Interfaces

Configuring Static IPsec Virtual Tunnel Interfaces

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. crypto IPsec profile profile-name
  4. set transform-set transform-set-name [transform-set-name2...transform-set-name6]
  5. exit
  6. interface type number
  7. ip address address mask
  8. tunnel mode ipsec ipv4
  9. tunnel source interface-type interface-number
  10. tunnel destination ip-address
  11. tunnel protection IPsec profile profile-name
  12. end

DETAILED STEPS

  Command or Action Purpose
Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

crypto IPsec profile profile-name

Example:


Device(config)# crypto IPsec profile PROF

Defines the IPsec parameters that are to be used for IPsec encryption between two IPsec devices, and enters IPsec profile configuration mode.

Step 4

set transform-set transform-set-name [transform-set-name2...transform-set-name6]

Example:


Device(ipsec-profile)# set transform-set tset

Specifies which transform sets can be used .

Step 5

exit

Example:

Device(ipsec-profile)# exit

Exits IPsec profile configuration mode, and enters global configuration mode.

Step 6

interface type number

Example:


Device(config)# interface tunnel 0

Specifies the interface on which the tunnel will be configured and enters interface configuration mode.

Step 7

ip address address mask

Example:


Device(config-if)# ip address 10.1.1.1 255.255.255.0

Specifies the IP address and mask.

Step 8

tunnel mode ipsec ipv4

Example:

Device(config-if)# tunnel mode ipsec ipv4

Defines the mode for the tunnel.

Step 9

tunnel source interface-type interface-number

Example:


Device(config-if)# tunnel source loopback 0

Specifies the tunnel source as a loopback interface.

Step 10

tunnel destination ip-address

Example:


Device(config-if)# tunnel destination 172.16.1.1

Identifies the IP address of the tunnel destination.

Step 11

tunnel protection IPsec profile profile-name

Example:


Device(config-if)# tunnel protection IPsec profile PROF

Associates a tunnel interface with an IPsec profile.

Step 12

end

Example:

Device(config-if)# end

Exits interface configuration mode and returns to privileged EXEC mode.

Configuring BGP over IPsec Virtual Tunnel Interfaces

Perform this task to optionally configure BGP over the virtual tunnel interfaces of two routers.

Before you begin

Perform steps in Configuring Static IPsec Virtual Tunnel Interfaces.

SUMMARY STEPS

  1. router bgp autonomous-system-number
  2. neighbor ip-address remote-as autonomous-system-number
  3. network network-ip-address mask subnet-mask
  4. exit
  5. Enter the following commands on the second router.
  6. router bgp autonomous-system-number
  7. neighbor ip-address remote-as autonomous-system-number
  8. network network-ip-address mask subnet-mask

DETAILED STEPS

  Command or Action Purpose
Step 1

router bgp autonomous-system-number

Example:

Device(config)# router bgp 65510

Enters router configuration mode and creates a BGP routing process.

autonomous-system-number —Number of an autonomous system that identifies the router to other BGP routers and tags the routing information that is passed along. Number in the range from 1 to 65535.

In the example, the first router in this procedure is identified as "65510".
Step 2

neighbor ip-address remote-as autonomous-system-number

Example:

Device(config-router)# neighbor 10.1.1.2 remote-as 65511

ip-address —IP address of the adjacent router's tunnel interface.

autonomous-system-number —Number of an autonomous system that identifies the router of the second router. Number in the range from 1 to 65535.

Step 3

network network-ip-address mask subnet-mask

Example:

Device(config-router)# network 2.2.2.0 mask 255.255.255.0

network-ip-address —IP address of the network advertised in BGP. For example, the IP address of a loopback interface.

subnet-mask —subnet mask of the network advertised in BGP.

Note 

The BGP network command network and mask must exactly match a route that is already in the routing table for it to be brought into BGP and advertised to BGP neighbors. This is different from EIGRP, OSPF where the network statement just has to "cover" an interface network and it will pick up the network with mask from the interface.

Step 4

exit

Example:

Device(config-router)# exit

Exits router configuration mode.

Step 5

Enter the following commands on the second router.
Step 6

router bgp autonomous-system-number

Example:

Device(config)# router bgp 65511

Enters router configuration mode and creates a BGP routing process.

autonomous-system-number —Number of an autonomous system that identifies the router to other BGP routers and tags the routing information that is passed along. Number in the range from 1 to 65535.

In the example, the second router in this procedure is identified as "65511".
Step 7

neighbor ip-address remote-as autonomous-system-number

Example:

Device(config-router)# neighbor 10.1.1.1 remote-as 65510

ip-address —IP address of the adjacent router's tunnel interface.

Step 8

network network-ip-address mask subnet-mask

Example:

Device(config-router)# network 1.1.1.0 mask 255.255.255.0

network-ip-address —IP address of the network advertised in BGP. For example, the IP address of a loopback interface.

subnet-mask —subnet mask of the network advertised in BGP.

Note 

Use the exact network IP address and subnet mask.

Configuring Dynamic IPsec Virtual Tunnel Interfaces

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. crypto ipsec profile profile-name
  4. set transform-set transform-set-name [transform-set-name2...transform-set-name6]
  5. exit
  6. interface virtual-template number type tunnel
  7. tunnel mode ipsec ipv4
  8. tunnel protection IPsec profile profile-name
  9. exit
  10. crypto isakamp profile profile-name
  11. match identity address ip-address mask
  12. virtual template template-number
  13. end

DETAILED STEPS

  Command or Action Purpose
Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

crypto ipsec profile profile-name

Example:

Device(config)# crypto ipsec profile PROF

Defines the IPsec parameters that are to be used for IPsec encryption between two IPsec devices and enters IPsec profile configuration mode.

Step 4

set transform-set transform-set-name [transform-set-name2...transform-set-name6]

Example:

Device(ipsec-profile)# set transform-set tset

Specifies which transform sets can be used with the crypto map entry.

Step 5

exit

Example:

Device(ipsec-profile)# exit

Exits ipsec profile configuration mode and enters global configuration mode.

Step 6

interface virtual-template number type tunnel

Example:

Device(config)# interface virtual-template 2 type tunnel

Defines a virtual-template tunnel interface and enters interface configuration mode.

Step 7

tunnel mode ipsec ipv4

Example:

Device(config-if)# tunnel mode ipsec ipv4

Defines the mode for the tunnel.

Step 8

tunnel protection IPsec profile profile-name

Example:

Device(config-if)# tunnel protection ipsec profile PROF

Associates a tunnel interface with an IPsec profile.

Step 9

exit

Example:

Device(config-if)# exit

Exits interface configuration mode.

Step 10

crypto isakamp profile profile-name

Example:

Device(config)# crypto isakamp profile profile1

Defines the ISAKMP profile to be used for the virtual template.

Step 11

match identity address ip-address mask

Example:

Device(conf-isa-prof)# match identity address 10.1.1.0 255.255.255.0

Matches an identity from the ISAKMP profile and enters isakmp-profile configuration mode.

Step 12

virtual template template-number

Example:

Device(config)# virtual-template 1

Specifies the virtual template attached to the ISAKMP profile.

Step 13

end

Example:

Device(config)# end

Exits global configuration mode and enters privileged EXEC mode.

Configuring Multi-SA Support for Dynamic Virtual Tunnel Interfaces Using IKEv1


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.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. ip vrf vrf-name
  4. rd route-distinguisher
  5. exit
  6. crypto keyring keyring-name
  7. pre-shared-key address key key
  8. exit
  9. crypto isakmp profile profile-name
  10. keyring keyring-name
  11. match identity address mask
  12. virtual-template template-number
  13. exit
  14. crypto ipsec transform-set transform-set-name transform1 [transform2] [transform3]
  15. exit
  16. crypto ipsec profile name
  17. set security-policy limit maximum-limit
  18. set transform-set transform-set-name [transform-set-name2 .... transform-set-name6]
  19. exit
  20. interface virtual-template number type tunnel
  21. ip vrf forwarding vrf-name
  22. ip unnumbered type number
  23. tunnel mode ipsec ipv4
  24. tunnel protection profile ipsec profile-name
  25. end

DETAILED STEPS

  Command or Action Purpose
Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

Step 2

configure terminal

Example:

Device# configure terminal
Enters global configuration mode.
Step 3

ip vrf vrf-name

Example:

Device(config)# ip vrf VRF-100-1
Defines the VRF instance and enters VRF configuration mode.
Step 4

rd route-distinguisher

Example:

Device(config-vrf)# rd 100:21

Creates routing and forwarding tables for a VRF.

Step 5

exit

Example:

Device(config-vrf)# exit
Exits VRF configuration mode and enters global configuration mode.
Step 6

crypto keyring keyring-name

Example:

Device(config)# crypto keyring cisco-100-1
Defines a crypto key ring and enters key ring configuration mode.
Step 7

pre-shared-key address key key

Example:

Device(config-keyring)# pre-shared-key address 10.1.1.1 key cisco-100-1
Defines the preshared key to be used for Internet Key Exchange (IKE) authentication.
Step 8

exit

Example:

Device(config-keyring)# exit
Exits keyring configuration mode and enters global configuration mode.
Step 9

crypto isakmp profile profile-name

Example:

Device(config)# crypto isakmp profile
cisco-isakmp-profile-100-1
Defines an ISAKMP profile and enters ISAKMP configuration mode.
Step 10

keyring keyring-name

Example:

Device(conf-isa-prof)# keyring cisco-100-1
Configures a key ring in ISAKMP mode.
Step 11

match identity address mask

Example:

Device(conf-isa-prof)# match identity address 10.1.1.0 255.255.255.0
Matches an identity from the ISAKMP profile.
Step 12

virtual-template template-number

Example:

Device(conf-isa-prof)# virtual-template 101
Specifies the virtual template that will be used to clone virtual access interfaces.
Step 13

exit

Example:

Device(conf-isa-prof)# exit
Exits ISAKMP profile configuration mode and enters global configuration mode.
Step 14

crypto ipsec transform-set transform-set-name transform1 [transform2] [transform3]

Example:

Device(config)# crypto ipsec transform-set cisco esp-aes esp-sha-hmac
Defines the transform set and enters crypto transform configuration mode.
Step 15

exit

Example:

Device(conf-crypto-trans)# exit
Exits crypto transform configuration mode and enters global configuration mode.
Step 16

crypto ipsec profile name

Example:

Device(config)# crypto ipsec profile cisco-ipsec-profile-101
Defines the IPsec parameters used for IPsec encryption between two IPsec devices, and enters IPsec profile configuration mode.
Step 17

set security-policy limit maximum-limit

Example:

Device(ipsec-profile)# set security-policy limit 3
Defines an upper limit to the number of flows that can be created for an individual virtual access interface.
Step 18

set transform-set transform-set-name [transform-set-name2 .... transform-set-name6]

Example:

Device(ipsec-profile)# set transform-set cisco
Specifies the transform sets to be used with the crypto map entry.
Step 19

exit

Example:

Device(ipsec-profile)# exit
Exits IPsec profile and enters global configuration mode.
Step 20

interface virtual-template number type tunnel

Example:

Device(config)# interface virtual-template 101 type tunnel
Creates a virtual template interface that can be configured interface and enters interface configuration mode.
Step 21

ip vrf forwarding vrf-name

Example:

Device(config-if)# ip vrf forwarding VRF-100-1
Associates a VRF instance with a virtual-template interface.
Step 22

ip unnumbered type number

Example:

Device(config-if)# ip unnumbered GigabitEthernet 0.0
Enables IP processing on an interface without assigning an explicit IP address to the interface.
Step 23

tunnel mode ipsec ipv4

Example:


Device(config-if)# tunnel mode ipsec ipv4

Defines the mode for the tunnel.

Step 24

tunnel protection profile ipsec profile-name

Example:

Device(config-if)# tunnel protection ipsec profile PROF
Associates a tunnel interface with an IPsec profile.
Step 25

end

Example:

Device(config-if)# end
Exits interface configuration mode, and returns to privileged EXEC mode.

Configuring IPsec Mixed Mode Support for SVTIs

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. crypto IPsec profile profile-name
  4. set transform-set transform-set-name [transform-set-name2...transform-set-name6]
  5. exit
  6. interface type number
  7. ip address address mask
  8. Do one of the following:
    • tunnel mode ipsec ipv4 v6-overlay
    • tunnel mode ipsec ipv6 v4-overlay
  9. tunnel source interface-type interface-type
  10. tunnel destination ip-address
  11. tunnel protection IPsec profile profile-name
  12. end

DETAILED STEPS

  Command or Action Purpose
Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

crypto IPsec profile profile-name

Example:


Device(config)# crypto IPsec profile PROF

Defines the IPsec parameters that are to be used for IPsec encryption between two IPsec devices, and enters IPsec profile configuration mode.

Step 4

set transform-set transform-set-name [transform-set-name2...transform-set-name6]

Example:


Device(ipsec-profile)# set transform-set tset

Specifies which transform sets can be used with the crypto map entry.

Step 5

exit

Example:

Device(ipsec-profile)# exit

Exits IPsec profile configuration mode, and enters global configuration mode.

Step 6

interface type number

Example:


Device(config)# interface tunnel 0

Specifies the interface on which the tunnel will be configured and enters interface configuration mode.

Step 7

ip address address mask

Example:


Device(config-if)# ip address 10.1.1.1 255.255.255.0

Specifies the IP address and mask.

Step 8

Do one of the following:

  • tunnel mode ipsec ipv4 v6-overlay
  • tunnel mode ipsec ipv6 v4-overlay

Example:

Device(config-if)# tunnel mode ipsec ipv4 v6-overlay

Defines the mode for the tunnel.

Step 9

tunnel source interface-type interface-type

Example:


Device(config-if)# tunnel source loopback 0

Specifies the tunnel source as a loopback interface.

Step 10

tunnel destination ip-address

Example:


Device(config-if)# tunnel destination 172.16.1.1

Identifies the IP address of the tunnel destination.

Step 11

tunnel protection IPsec profile profile-name

Example:


Device(config-if)# tunnel protection IPsec profile PROF

Associates a tunnel interface with an IPsec profile.

Step 12

end

Example:

Device(config-if)# end

Exits interface configuration mode and returns to privileged EXEC mode.

Configuring IPsec Mixed Mode Support for Dynamic VTIs

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. crypto ipsec profile profile-name
  4. set mixed mode
  5. set transform-set transform-set-name [transform-set-name2...transform-set-name6]
  6. exit
  7. interface virtual-template number type tunnel
  8. tunnel mode ipsec ipv4
  9. tunnel protection IPsec profile profile-name
  10. exit
  11. crypto isakamp profile profile-name
  12. match identity address ip-address mask
  13. virtual template template-number
  14. end

DETAILED STEPS

  Command or Action Purpose
Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

crypto ipsec profile profile-name

Example:

Device(config)# crypto ipsec profile PROF

Defines the IPsec parameters that are to be used for IPsec encryption between two IPsec devices and enters IPsec profile configuration mode.

Step 4

set mixed mode

Example:

Device(config)# set mixed mode

Defines the IPsec parameters that are to be used for IPsec encryption between two IPsec devices and enters IPsec profile configuration mode.

Step 5

set transform-set transform-set-name [transform-set-name2...transform-set-name6]

Example:

Device(ipsec-profile)# set transform-set tset

Specifies which transform sets can be used with the crypto map entry.

Step 6

exit

Example:

Device(ipsec-profile)# exit

Exits ipsec profile configuration mode and enters global configuration mode.

Step 7

interface virtual-template number type tunnel

Example:

Device(config)# interface virtual-template 2 type tunnel

Defines a virtual-template tunnel interface and enters interface configuration mode.

Step 8

tunnel mode ipsec ipv4

Example:

Device(config-if)# tunnel mode ipsec ipv4

Defines the mode for the tunnel.

Step 9

tunnel protection IPsec profile profile-name

Example:

Device(config-if)# tunnel protection ipsec profile PROF

Associates a tunnel interface with an IPsec profile.

Step 10

exit

Example:

Device(config-if)# exit

Exits interface configuration mode.

Step 11

crypto isakamp profile profile-name

Example:

Device(config)# crypto isakamp profile profile1

Defines the ISAKMP profile to be used for the virtual template.

Step 12

match identity address ip-address mask

Example:

Device(conf-isa-prof)# match identity address 10.1.1.0 255.255.255.0

Matches an identity from the ISAKMP profile and enters isakmp-profile configuration mode.

Step 13

virtual template template-number

Example:

Device(config)# virtual-template 1

Specifies the virtual template attached to the ISAKMP profile.

Step 14

end

Example:

Device(config)# end

Exits global configuration mode and enters privileged EXEC mode.

Configuration Examples for IPsec Virtual Tunnel Interfaces

Example: Static Virtual Tunnel Interface with IPsec

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

Router Configuration 


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
 
 load-interval 30
 tunnel source 10.0.149.203
 tunnel destination 10.0.149.217
 tunnel mode IPsec ipv4
 tunnel protection IPsec profile P1
!
 
 ip address 10.0.149.203 255.255.255.0
 duplex full
!
 
 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

Router Configuration 


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
 
 tunnel source 10.0.149.217
 tunnel destination 10.0.149.203
 tunnel mode ipsec ipv4
 tunnel protection ipsec profile P1
!
interface 
 ip address 10.0.149.217 255.255.255.0
 speed 100
 full-duplex
!
interface 
 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

Example: Verifying the Results for the IPsec Static Virtual Tunnel Interface

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.

Verifying the IPsec Static Virtual Tunnel Interface

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,
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

Example: VRF-Aware Static Virtual Tunnel Interface

To add the VRF to the static VTI example, include the ip vrf and ip vrf forwarding commands to the configuration as shown in the following example.

Cisco 7206 Router Configuration


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

Example: Static Virtual Tunnel Interface with QoS

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.

Cisco 7206 Router Configuration


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

Example: Static Virtual Tunnel Interface with Virtual Firewall

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:

Cisco 7206 Router Configuration


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

Example: Dynamic Virtual Tunnel Interface Easy VPN Server

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.

Cisco 7206 Router Configuration


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

Example: Verifying the Results for the Dynamic Virtual Tunnel Interface Easy VPN Server

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

Example: VRF-Aware IPsec with a Dynamic VTI When VRF Is Configured Under a Virtual Template

The following example shows how to configure VRF-aware IPsec under a virtual template to take advantage of the DVTI: 


hostname cisco 7206
!
ip vrf VRF-100-1 
  rd 1:1
!
ip vrf VRF-100-2 
  rd 1:1
!
!
!
crypto keyring cisco-100-1 
  pre-shared-key address 10.1.1.1 key cisco-100-1
crypto keyring cisco-100-2 
  pre-shared-key address 10.1.2.1 key cisco-100-2
crypto isakmp profile cisco-isakmp-profile-100-1 
  keyring cisco-100-1 
  match identity address 10.1.1.0 255.255.255.0 
  virtual-template 101
crypto isakmp profile cisco-isakmp-profile-100-2 
  keyring cisco-100-2 
  match identity address 10.1.2.0 255.255.255.0 
  virtual-template 102
!
!
crypto ipsec transform-set cisco esp-aes esp-sha-hmac 
!
crypto ipsec profile cisco-ipsec-profile-101 
  set security-policy limit 3 
  set transform-set cisco 
!
crypto ipsec profile cisco-ipsec-profile-102 
  set security-policy limit 5 
  set transform-set Cisco
!
interface Virtual-Template101 type tunnel 
  ip vrf forwarding VRF-100-1 
  ip unnumbered Ethernet 0/0 
  tunnel mode ipsec ipv4 
  tunnel protection ipsec profile cisco-ipsec-profile-101
!
interface Virtual-Template102 type tunnel 
  ip vrf forwarding VRF-100-2 
  ip unnumbered Ethernet 0/0 
  tunnel mode ipsec ipv4 
  tunnel protection ipsec profile cisco-ipsec-profile-102
!

Example: VRF-Aware IPsec with Dynamic VTI When VRF Is Configured Under a Virtual Template with the Gateway Option in an IPsec Profile

The following example shows how to configure VRF-aware IPsec to take advantage of the DVTI, when the VRF is configured under a virtual template with the gateway option in an IPsec profile. 

hostname ASR 1000
!
ip vrf VRF-100-1
 rd 1:1
!
ip vrf VRF-100-2
 rd 1:1
!
!
!
crypto keyring cisco-100-1
 pre-shared-key address 10.1.1.1 key cisco-100-1
crypto keyring cisco-100-2
 pre-shared-key address 10.1.2.1 key cisco-100-2
crypto isakmp profile cisco-isakmp-profile-100-1
 keyring cisco-100-1
 match identity address 10.1.1.0 255.255.255.0
 virtual-template 101
crypto isakmp profile cisco-isakmp-profile-100-2
 keyring cisco-100-2
 match identity address 10.1.2.0 255.255.255.0
 virtual-template 102
!
!
crypto ipsec transform-set cisco esp-3des esp-sha-hmac
!
crypto ipsec profile cisco-ipsec-profile-101
 set security-policy limit 3
 set transform-set cisco
 set reverse-route gateway 172.16.0.1
!
crypto ipsec profile cisco-ipsec-profile-102
 set security-policy limit 5
 set transform-set cisco
 set reverse-route gateway 172.16.0.1
!
interface Virtual-Template101 type tunnel
 ip vrf forwarding VRF-100-1
 ip unnumbered Ethernet 0/0
 tunnel mode ipsec ipv4
 tunnel protection ipsec profile cisco-ipsec-profile-101
!
interface Virtual-Template102 type tunnel
 ip vrf forwarding VRF-100-2
 ip unnumbered Ethernet 0/0
 tunnel mode ipsec ipv4
 tunnel protection ipsec profile cisco-ipsec-profile-102
!

Example: VRF-Aware IPsec with a Dynamic VTI When VRF Is Configured Under an ISAKMP Profile 


hostname cisco 7206        
!
ip vrf VRF-100-1 
  rd 1:1
!
ip vrf VRF-100-2 
  rd 1:1
! 
crypto keyring cisco-100-1 
  pre-shared-key address 10.1.1.1 key cisco-100-1
crypto keyring cisco-100-2 
  pre-shared-key address 10.1.2.1 key cisco-100-2
crypto isakmp profile cisco-isakmp-profile-100-1 
  vrf VRF-100-1 
  keyring cisco-100-1 
  match identity address 10.1.1.0 255.255.255.0 
  virtual-template 1
crypto isakmp profile cisco-isakmp-profile-100-2 
  vrf VRF-100-2 
  keyring cisco-100-2 
  match identity address 10.1.2.0 255.255.255.0 
  virtual-template 1
!
!
crypto ipsec transform-set cisco esp-aes esp-sha-hmac 
crypto ipsec profile cisco-ipsec-profile 
  set security-policy limit 3 
  set transform-set cisco 
!
!
!
interface Virtual-Template 1 type tunnel 
  ip unnumbered ethernet 0/0 
  tunnel mode ipsec ipv4 
  tunnel protection ipsec profile cisco-ipsec-profile
!
!

Example: VRF-Aware IPsec with a Dynamic VTI When VRF Is Configured Under an ISAKMP Profile and a Gateway Option in an IPsec Profile

The following example shows how to configure VRF-aware IPsec to take advantage of the DVTI, when the VRF is configured under an ISAKMP profile and a gateway option in an IPsec profile: 


hostname ASR 1000
!
ip vrf VRF-100-1
 rd 1:1
!
ip vrf VRF-100-2
 rd 1:1
!
crypto keyring cisco-100-1
 pre-shared-key address 10.1.1.1 key cisco-100-1
crypto keyring cisco-100-2
 pre-shared-key address 10.1.2.1 key cisco-100-2
crypto isakmp profile cisco-isakmp-profile-100-1
 vrf VRF-100-1
 keyring cisco-100-1
 match identity address 10.1.1.0 255.255.255.0
 virtual-template 1
crypto isakmp profile cisco-isakmp-profile-100-2
 vrf VRF-100-2
 keyring cisco-100-2
 match identity address 10.1.2.0 255.255.255.0
 virtual-template 1
!
!
crypto ipsec transform-set cisco esp-3des esp-sha-hmac
crypto ipsec profile cisco-ipsec-profile
 set security-policy limit 3
 set transform-set cisco
 set reverse-route gateway 172.16.0.1
!
!
!
interface Virtual-Template1 type tunnel
 ip unnumbered Ethernet 0/0
 tunnel mode ipsec ipv4
 tunnel protection ipsec profile cisco-ipsec-profile
!
!

Example: VRF-Aware IPsec with a Dynamic VTI When a VRF Is Configured Under Both a Virtual Template and an ISAKMP Profile


Note
When separate VRFs are configured under an ISAKMP profile and a virtual template, the VRF configured under the virtual template takes precedence. This configuration is not recommended.

The following example shows how to configure VRF-aware IPsec to take advantage of the DVTI when the VRF is configured under both a virtual template and an ISAKMP profile: 

hostname ASR 1000
.
.
.
ip vrf test-vti2
 rd 1:2 
 route-target export 1:1 
 route-target import 1:1
!
.
.
.
ip vrf test-vti1
 rd 1:1
 route-target export 1:1 
 route-target import 1:1
!
.
.
.
crypto isakmp profile cisco-isakmp-profile
 vrf test-vti2 
 keyring key
 match identity address 10.1.1.0 255.255.255.0
!
.
.
.
interface Virtual-Template1 type tunnel
 ip vrf forwarding test-vti1 
 ip unnumbered Loopback 0  
 ip virtual-reassembly
 tunnel mode ipsec ipv4
 tunnel protection ipsec profile test-vti1
!
.
.
.
end

Example: Dynamic Virtual Tunnel Interface with Virtual Firewall

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

Example: Dynamic Virtual Tunnel Interface with QoS

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

Additional References for IPsec Virtual Tunnel Interface

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

Security commands

IPsec configuration

Configuring Security for VPNs with IPsec

QoS configuration

Cisco IOS Quality of Service Solutions Configuration Guide

EasyVPN configuration

  • Cisco Easy VPN Remote

  • Easy VPN Server

Recommended cryptographic algorithms

Next Generation Encryption

Standards and RFCs

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)

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for IPsec Virtual Tunnel Interfaces

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.

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.
Table 1. Feature Information for IPsec Virtual Tunnel Interfaces

Feature Name

Releases

Feature Configuration Information

Dynamic IPsec VTIs

Cisco IOS XE Release 2.1

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.

FlexVPN Mixed Mode Support

Cisco IOS XE Release 3.10S

The FlexVPN Mixed Mode feature provides support for carrying IPv4 traffic over IPsec IPv6 transport. This is the first phase towards providing dual stack support on the IPsec stack. This implementation does not support using a single IPsec security association (SA) pair for both IPv4 and IPv6 traffic.

This feature is only supported for Remote Access VPN with IKEv2 and Dynamic VTI.

Multi-SA for Dynamic VTIs

Cisco IOS XE Release 3.2S

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

Cisco IOS XE Release 2.1

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.

Tunnel Mode Auto Selection

Cisco IOS XE Release 3.12S

The Tunnel Mode Auto Selection feature eases the configuration and spares you about knowing the responder’s details. This feature automatically applies the tunneling protocol (GRE or IPsec) and transport protocol (IPv4 or IPv6) on the virtual template as soon as the IKE profile creates the virtual access interface.

The following command was introduced or modified: virtual-template

FlexVPN Mixed Mode v6 over v4 Transport

Cisco IOS XE Everest 16.4.1

The FlexVPN Mixed Mode v6 over v4 Transport feature provides support for carrying IPv6 traffic over IPsec IPv4 transport. This implementation does not support using a single IPsec security association (SA) pair for both IPv4 and IPv6 traffic.