Implement DVTI on Secure Firewall and Cisco IOS

Introduction

This document describes how to implement a Dynamic Virtual Tunnel Interface hub and spoke solution with EIGRP on Adaptive Security Appliance.

Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

• Basic understanding of Virtual Tunnel Interfaces on ASA
• Basic underlay connectivity between Hub/Spokes/ISP
• Basic understanding of EIGRP

• Adaptive Security Appliance version 9.19(1) or higher

Components Used

The information in this document is based on these software and hardware versions:

• Two ASAv devices, both version 9.19(1). Utilized for Spoke 1 and the Hub
• Two Cisco IOS® v devices version 15.9(3)M4. One for ISP device, one utilized for Spoke 2.
• Two Ubuntu hosts to generic traffic meant for the tunnels

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, ensure that you understand the potential impact of any command.

Configure

Network Diagram

Configurations

Configure the WAN Interface and IKEv2 crypto parameters on the Hub ASA

Enter configuration mode on the hub.

interface g0/0
ip address 198.51.100.1 255.255.255.0 
nameif OUTSIDE

Configure the IKEv2 Parameters on the Hub ASA

Create an IKEv2 policy that defines the Phase 1 parameters of the IKE connection.

crypto ikev2 policy 1      (The number is locally significant on the device, this determine the order in which the IKEv2 policies are presented to the peer)
encryption aes-256         (Defines the encryption parameter used to encrypt the initial communication between the devices)
integrity sha256           (Defines the integrity used to secure the initial communication between the devices)
group 21                   (Defines the Diffie-Hellman group used to protect the key exchange between devices)
prf sha256                 (Pseudo Random Function, an optional value to define, automatically chooses the value defined for integrity)
lifetime seconds 86400     (Controls the phase 1 rekey, specified in seconds. Optional value, as the default is 86400)

Create an IKEv2 IPsec-proposal to define the Phase 2 parameters used to protect the traffic.

crypto ipsec ikev2 ipsec-proposal NAME                (Name is locally signicant and is used as a reference point later in the configuration)
protocol esp encryption aes-256                       (specifies that Encapsulating Security Payload and aes-256 is used to encrypt the traffic traversing the tunnel)
protocol esp integrity sha-256                        (specifies that Encapsulating Security Payload and sha-256 is used to ensure the integrity of the traffic traversing the tunnel)

Create an IPsec profile that contains the IPsec-proposal.

crypto ipsec profile NAME                    (This name is referenced on the Virtual-Template Interface to allow the crypto parameters to be utilized)
set ikev2 ipsec-proposal NAME                (This is the name previously used when creating the ipsec-proposal)

Create a Loopback and Virtual-Template Interface

interface loopback 1
ip address 172.16.50.254 255.255.255.255        (This IP address is used for all of the Virtual-Access Interfaces spawned from the Virtual-Template)
nameif LOOP1

interface Virtual-Template 1 type tunnel
ip unnumbered LOOP1                                (Borrows the IP address specified in Loopback1 for all Virtual-Access Interfaces) 
nameif DVTI
tunnel source Interface OUTSIDE                    (Specifies the Interface that the tunnel terminates on, commonly used as the WAN Interface)
tunnel mode ipsec ipv4                             (Specifies that the mode uses ipsec, and uses ipv4)
tunnel protection ipsec profile NAME               (Reference the name of the previously created ipsec profile)

Create a Tunnel-group and Advertise the Tunnel Interface IPs via IKEv2 Exchange

Create a tunnel-group to specify type of tunnel and method of authentication.

tunnel-group DefaultL2LGroup ipsec-attributes             ('DefaultL2LGroup' is a default tunnel-group used for hub DVTI with pre-shared keys, this applied with the virtual template allows dynamic spoke connections)
virtual-template 1                                        (This command ties the Virtual-Template previously created to the tunnel-group to allow for proper authentication and connection)
ikev2 remote-authentication pre-shared-key cisco123       (This specifies the remote authentication as a pre-shared-key with the key being cisco123)
ikev2 local-authentication pre-shared-key cisco123        (This specifies the local authentication as a pre-shared-key with the key being cisco123)
ikev2 route set Interface                                 (Advertises the VTI Interface IP over IKEv2 exchanges. Enables unicast reachability between VTI Interfaces for BGP or path monitoring to work over the tunnel)

Configue EIGRP Routing on the Hub ASA

router eigrp 100 
network 172.16.50.254 255.255.255.255         (Advertise the IP address of the Loopback used for the Virtual-Template. This is used to form an EIGRP neighborship via VTI connectivity) 

Configure the Interfaces on the Spoke ASA

Configure the WAN Interface.

interface g0/1
ip address 203.0.113.1 255.255.255.0
nameif OUTSIDE-SPOKE-1

Configure the LAN Interface.

interface g0/0
ip address 10.45.0.4 255.255.255.0
nameif INSIDE-SPOKE-1

Configure a Loopback Interface.

interface loopback1
ip address 172.16.50.1 255.255.255.255
nameif Loop1

Configure the IKEv2 Crypto Parameters on the Spoke ASA

Create an IKEv2 policy that matches the parameters on the hub.

crypto ikev2 policy 1
encryption aes-256
integrity sha256
group 21         
prf sha256
lifetime 86400

Create an IKEv2 IPsec-proposal that matches the parameters on the hub.

crypto ipsec ikev2 ipsec-proposal NAME           (Name is locally signicant, this does not need to match the hub device.)
protocol esp encryption aes-256
protocol esp integrity sha-256

Create an IPsec profile that contains the IPsec-proposal.

crypto ipsec profile NAME               (This name is locally significant and is referenced in the SVTI configuration.)
set ikev2 ipsec-proposal NAME           (This is the name previously used when creating the ipsec-proposal.)

Configure the Static Virtual Tunnel Interface on the Spoke ASA

Configure a static Virtual Tunnel Interface pointing to the hub. The spoke devices configure regular static Virtual Tunnel Interfaces to the hub, only the hub requires a Virtual-Template.

interface tunnel1
ip unnumbered loopback1
nameif ASA-SPOKE-SVTI
tunnel destination  198.51.100.254          (Tunnel destination references the Hub ASA tunnel source. Commonly referred to as the WAN address.)
tunnel mode ipsec ipv4
tunnel protection ipsec profile NAME

Create a Tunnel-Group and Advertise the Tunnel Interface IPs via IKEv2 Exchange

tunnel-group 198.51.100.1 type ipsec-l2l                   (This specifies the connection type as ipsec-L2L (Lan-to-Lan), using the IKE ID of the hub device.)
tunnel-group 198.51.100.1 ipsec-attributes                 (Ipsec attributes allows you to make changes to the method of authentication and parameters used.)
ikev2 remote-authentication pre-shared-key cisco123 
ikev2 local-authentication pre-shared-key cisco123
ikev2 route set Interface

Configure EIGRP Routing on the Spoke ASA

Create an EIGRP autonomous system and apply the desired networks to be advertised.

router eigrp 100
network 10.45.0.0 255.255.255.0        (Advertises the Host-A network to the hub. This allows the hub to notify connecting spokes how to reach this network.)
network 172.16.50.1 255.255.255.255    (Advertises and utilizes the tunnel IP address to form an EIGRP neighborship.)

Configure the Interfaces on the Spoke Router

interface g0/0
ip address 192.0.2.1 255.255.255.0
no shut

interface g0/1
ip address 10.12.0.2
no shut

interface loopback1
ip address 172.16.50.2 255.255.255.255

Configure the IKEv2 Parameters and AAA on the Spoke Router

Create an IKEv2 proposal to match the Phase 1 parameters on the ASA.

crypto ikev2 proposal NAME       (These parameters must match the ASA IKEv2 Policy.) 
encryption aes-cbc-256           (aes-cbc-256 is the same as the ASA aes-256. However, AES-GCM of any variant is not the same, 
                                  and is not a matching parameter with plain AES.)
integrity sha256
group 21

Create an IKEv2 policy to attach the proposal(s).

crypto ikev2 policy NAME
proposal NAME               (This is the name of the IKEv2 proposal created in the step ikev2.)

Create an IKEv2 authorization policy.

crypto ikev2 authorization policy NAME   (IKEv2 authorization policy serves as a container of IKEv2 local AAA group authorization parameters.)
route set Interface

Enable AAA on the device.

aaa new-model 

Create an AAA authorization network.

aaa authorization network NAME local    (Creates a name and method for aaa authorization that is referenced in the IKEv2 profile along with the IKEv2 authorization policy.)

Create an IKEv2 Profile that contains a repository of the nonnegotiable parameters of the IKE SA, such as local or remote identities and authentication methods.

crypto ikev2 profile NAME                           
match identity remote address  198.51.100.1    (Used to match the address of the Hub VTI source Interface, can also be 0.0.0.0 to match any peer address but this is not best practice.)
identity local address  192.0.2.1              (Defines the local IKE-ID of the router for this IKEv2 profile.)
authentication remote pre-share key cisco123
authentication local pre-share key cisco123
no config-exchange request                     (Applies to Cisco IOS, Cisco IOS-XE devices do this by default. This stops the device from sending IKEv2 config-exchange requests to the ASA, 
                                                which is unsupported on the ASA.)
aaa authorization group psk list NAME NAME     (Specifies an AAA method list and username for group. The first NAME is the aaa network name, the second NAME is the IKEv2 authorization policy.)

Create a transform set to define the encryption and hashing parameters used to protect the tunneled traffic.

crypto ipsec transform-set NAME esp aes 256 esp-sha256-hmac

Create a crypto IPsec profile to house the transform-set and IKEv2 profile.

crypto ipsec profile NAME                  (Define the name of the ipsec-profile.)
set transform-set NAME                     (Reference the name of the created transform set.)
set ikev2-profile NAME                     (Reference the name of the created IKEv2 profile.)

Configure the Static Virtual Tunnel Interface on the Spoke Router

Configure a static Virtual Tunnel Interface pointing to the hub.

interface tunnel1
ip unnumbered loopback1
tunnel source g0/0
tunnel mode ipsec ipv4
tunnel destination 198.51.100.1
tunnel protection ipsec profile NAME      (Reference the name of the created ipsec profile. This applies the IKEv2 
                                           and transform set parameters to the tunnel Interface.)

Configue EIGRP Routing on the Spoke Router

Create an EIGRP autonomous system and apply the desired networks to be advertised.

router eigrp 100
network 172.16.50.2 0.0.0.0     (Routers advertise EIGRP networks with the wildcard mask. 
                                 This advertises the tunnel IP address to allow the device to form an EIGRP neighborship via the tunnel.)
network 10.12.0.0 0.0.0.255      (Advertises the Host-B network to the hub. This allows the hub to notify connecting spokes how to reach this network.

Verify

Use this section in order to confirm that your configuration works properly.

ASA Routing:

show run router

show eigrp topology

show eigrp neighbors

show route [eigrp]

ASA Crypto:

show run crypto ikev2

show run crypto ipsec

show run tunnel-group [NAME]

show crypto ikev2 sa

show crypto ipsec sa peer X.X.X.X

ASA Virtual-Template and Virtual-Accesses:

show run interface virtual-template # type tunnel

show interface virtual-access #

Cisco IOS Routing:

show run | sec eigrp

show ip eigrp topology

show ip eigrp neighbors

show ip route

show ip route eigrp

Cisco IOS Crypto:

show run | sec cry

show crypto ikev2 sa

show crypto ipsec sa peer X.X.X.X

Cisco IOS Tunnel Interface:

show run interface tunnel#

Troubleshoot

This section provides information you can use in order to troubleshoot your configuration.

ASA Debugs:

debug crypto ikev2 platform 255

debug crypto ikev2 protocol 255

debug crypto ipsec 255

debug ip eigrp #

debug ip eigrp neighbor X.X.X.X

Cisco IOS Debugs:

debug crypto ikev2 

debug crypto ikev2 error

debug crypto ikev2 packet

debug crypto ikev2 internal 

debug crypto ipsec 

debug crypto ipsec error

debug ip eigrp # 

debug ip eigrp neighbor X.X.X.X

Related Information

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