CLI example: Configuring an IKEv2-based IPsec NAT traversal tunnel for IPv4 packets between gateways

Network configuration

As shown in Figure 1, Device A is behind the NAT device. Configure an IKE-based IPsec tunnel between Device A and Device B to secure the communication between subnet 10.1.1.0/24 and subnet 10.1.2.0/24.

Figure 1 Network diagram

Software versions used

This configuration example was created and verified on E8371 of the F5000-AI160 device.

Procedures

Configuring Device A

1.        Assign IP addresses to interfaces:

# Assign an IP address to interface GigabitEthernet 1/0/1.

<DeviceA> system-view

[DeviceA] interface gigabitethernet 1/0/1

[DeviceA-GigabitEthernet1/0/1] ip address 1.1.1.1 255.255.0.0

[DeviceA-GigabitEthernet1/0/1] quit

# Assign IP addresses to other interfaces in the same way. (Details not shown.)

2.        Configure settings for routing.

This example configures static routes, and the next hop in the routes is 1.1.1.2.

[DeviceA] ip route-static 10.1.2.0 24 1.1.1.2

[DeviceA] ip route-static 2.2.2.2 16 1.1.1.2

3.        Add interfaces to security zones.

[DeviceA] security-zone name trust

[DeviceA-security-zone-Trust] import interface gigabitethernet 1/0/2

[DeviceA-security-zone-Trust] quit

[DeviceA] security-zone name untrust

[DeviceA-security-zone-Untrust] import interface gigabitethernet 1/0/1

[DeviceA-security-zone-Untrust] quit

4.        Configure a security policy:

Configure rules to permit traffic between the Untrust and Local security zones, so the devices can set up an IPsec tunnel:

# Configure a rule named ipseclocalout to allow Device A to send IPsec negotiation packets to Device B.

[DeviceA] security-policy ip

[DeviceA-security-policy-ip] rule name ipseclocalout

[DeviceA-security-policy-ip-1-ipseclocalout] source-zone local

[DeviceA-security-policy-ip-1-ipseclocalout] destination-zone untrust

[DeviceA-security-policy-ip-1-ipseclocalout] source-ip-host 1.1.1.1

[DeviceA-security-policy-ip-1-ipseclocalout] destination-ip-host 2.2.2.2

[DeviceA-security-policy-ip-1-ipseclocalout] action pass

[DeviceA-security-policy-ip-1-ipseclocalout] quit

# Configure a rule named ipseclocalin to allow Device A to receive the IPsec negotiation packets sent from Device B.

[DeviceA-security-policy-ip] rule name ipseclocalin

[DeviceA-security-policy-ip-2-ipseclocalin] source-zone untrust

[DeviceA-security-policy-ip-2-ipseclocalin] destination-zone local

[DeviceA-security-policy-ip-2-ipseclocalin] source-ip-host 2.2.2.2

[DeviceA-security-policy-ip-2-ipseclocalin] destination-ip-host 1.1.1.1

[DeviceA-security-policy-ip-2-ipseclocalin] action pass

[DeviceA-security-policy-ip-2-ipseclocalin] quit

Configure rules to permit the traffic between Host A and Host B:

# Configure a rule named trust-untrust to permit the packets from Host A to Host B.

[DeviceA-security-policy-ip] rule name trust-untrust

[DeviceA-security-policy-ip-3-trust-untrust] source-zone trust

[DeviceA-security-policy-ip-3-trust-untrust] destination-zone untrust

[DeviceA-security-policy-ip-3-trust-untrust] source-ip-subnet 10.1.1.0 24

[DeviceA-security-policy-ip-3-trust-untrust] destination-ip-subnet 10.1.2.0 24

[DeviceA-security-policy-ip-3-trust-untrust] action pass

[DeviceA-security-policy-ip-3-trust-untrust] quit

# Configure a rule named untrust-trust to permit the packets from Host B to Host A.

[DeviceA-security-policy-ip] rule name untrust-trust

[DeviceA-security-policy-ip-4-untrust-trust] source-zone untrust

[DeviceA-security-policy-ip-4-untrust-trust] destination-zone trust

[DeviceA-security-policy-ip-4-untrust-trust] source-ip-subnet 10.1.2.0 24

[DeviceA-security-policy-ip-4-untrust-trust] destination-ip-subnet 10.1.1.0 24

[DeviceA-security-policy-ip-4-untrust-trust] action pass

[DeviceA-security-policy-ip-4-untrust-trust] quit

[DeviceA-security-policy-ip] quit

5.        Define the data flows to be protected:

# Configure IPv4 advanced ACL 3101 to identify traffic from subnet 10.1.1.0/24 to subnet 10.1.2.0/24.

[DeviceA] acl advanced 3101

[DeviceA-acl-ipv4-adv-3101] rule 0 permit ip source 10.1.1.0 0.0.0.255 destination 10.1.2.0 0.0.0.255

[DeviceA-acl-ipv4-adv-3101] quit

6.        Configure an IPsec transform set to specify the packet encapsulation mode, security protocols, and algorithms.

The IPsec transform set settings at both sides of the IPsec tunnel must be the same.

[DeviceA] ipsec transform-set transform1

[DeviceA-ipsec-transform-set-transform1] protocol esp

[DeviceA-ipsec-transform-set-transform1] esp encryption-algorithm 3des-cbc

[DeviceA-ipsec-transform-set-transform1] esp authentication-algorithm md5

[DeviceA-ipsec-transform-set-transform1] quit

7.        Configure an IKEv2 keychain to specify the key information used for IKEv2 communication.

The preshared key used by both sides of the communication must be the same.

[DeviceA] ikev2 keychain keychain1

[DeviceA-ikev2-keychain-keychain1] peer peer1

[DeviceA-ikev2-keychain-keychain1-peer-peer1] address 2.2.2.2 16

[DeviceA-ikev2-keychain-keychain1-peer-peer1] identity address 2.2.2.2

[DeviceA-ikev2-keychain-keychain1-peer-peer1] pre-shared-key plaintext 123

[DeviceA-ikev2-keychain-keychain1-peer-peer1] quit

[DeviceA-ikev2-keychain-keychain1] quit

8.        Configure an IKEv2 profile to specify the security parameters used for setting up IKE SAs.

[DeviceA] ikev2 profile profile1

[DeviceA-ikev2-profile-profile1] keychain keychain1

[DeviceA-ikev2-profile-profile1] identity local fqdn www.devicea.com

[DeviceA-ikev2-profile-profile1] match remote identity address 2.2.2.2 255.255.0.0

[DeviceA-ikev2-profile-profile1] authentication-method local pre-share

[DeviceA-ikev2-profile-profile1] authentication-method remote pre-share

[DeviceA-ikev2-profile-profile1] quit

9.        Configure an IPsec policy to establish an IPsec tunnel to protect the specified data.

[DeviceA] ipsec policy policy1 1 isakmp

[DeviceA-ipsec-policy-isakmp-policy1-1] remote-address 2.2.2.2

[DeviceA-ipsec-policy-isakmp-policy1-1] transform-set transform1

[DeviceA-ipsec-policy-isakmp-policy1-1] security acl 3101

[DeviceA-ipsec-policy-isakmp-policy1-1] ikev2-profile profile1

[DeviceA-ipsec-policy-isakmp-policy1-1] quit

10.     Apply the IPsec policy to GigabitEthernet 1/0/1 to protect the traffic on the interface.

[DeviceA] interface gigabitethernet 1/0/1

[DeviceA-GigabitEthernet1/0/1] ipsec apply policy policy1

[DeviceA-GigabitEthernet1/0/1] quit

Configuring Device B

1.        Assign IP addresses to interfaces:

# Assign an IP address to interface GigabitEthernet 1/0/1.

<DeviceB> system-view

[DeviceB] interface gigabitethernet 1/0/1

[DeviceB-GigabitEthernet1/0/1] ip address 2.2.2.2 255.255.0.0

[DeviceB-GigabitEthernet1/0/1] quit

# Assign IP addresses to other interfaces in the same way. (Details not shown.)

2.        Configure settings for routing.

This example configures static routes, and the next hop in the routes is 2.2.2.1.

[DeviceB] ip route-static 10.1.1.0 24 2.2.2.1

[DeviceB] ip route-static 1.1.1.1 16 2.2.2.1

3.        Add interfaces to security zones.

[DeviceB] security-zone name trust

[DeviceB-security-zone-Trust] import interface gigabitethernet 1/0/2

[DeviceB-security-zone-Trust] quit

[DeviceB] security-zone name untrust

[DeviceB-security-zone-Untrust] import interface gigabitethernet 1/0/1

[DeviceB-security-zone-Untrust] quit

4.        Configure a security policy:

Configure rules to permit traffic between the Untrust and Local security zones, so the devices can set up an IPsec tunnel:

# Configure a rule named ipseclocalout to allow Device B to send IPsec negotiation packets to Device A.

[DeviceB] security-policy ip

[DeviceB-security-policy-ip] rule name ipseclocalout

[DeviceB-security-policy-ip-1-ipseclocalout] source-zone local

[DeviceB-security-policy-ip-1-ipseclocalout] destination-zone untrust

[DeviceB-security-policy-ip-1-ipseclocalout] source-ip-host 2.2.2.2

[DeviceB-security-policy-ip-1-ipseclocalout] destination-ip-host 3.3.3.1

[DeviceB-security-policy-ip-1-ipseclocalout] action pass

[DeviceB-security-policy-ip-1-ipseclocalout] quit

# Configure a rule named ipseclocalin to allow Device B to receive the IPsec negotiation packets sent from Device A.

[DeviceB-security-policy-ip] rule name ipseclocalin

[DeviceB-security-policy-ip-2-ipseclocalin] source-zone untrust

[DeviceB-security-policy-ip-2-ipseclocalin] destination-zone local

[DeviceB-security-policy-ip-2-ipseclocalin] source-ip-host 3.3.3.1

[DeviceB-security-policy-ip-2-ipseclocalin] destination-ip-host 2.2.2.2

[DeviceB-security-policy-ip-2-ipseclocalin] action pass

[DeviceB-security-policy-ip-2-ipseclocalin] quit

Configure rules to permit the traffic between Host B and Host A:

# Configure a rule named trust-untrust to permit the packets from Host B to Host A.

[DeviceB-security-policy-ip] rule name trust-untrust

[DeviceB-security-policy-ip-3-trust-untrust] source-zone trust

[DeviceB-security-policy-ip-3-trust-untrust] destination-zone untrust

[DeviceB-security-policy-ip-3-trust-untrust] source-ip-subnet 10.1.2.0 24

[DeviceB-security-policy-ip-3-trust-untrust] destination-ip-subnet 10.1.1.0 24

[DeviceB-security-policy-ip-3-trust-untrust] action pass

[DeviceB-security-policy-ip-3-trust-untrust] quit

# Configure a rule named untrust-trust to permit the packets from Host A to Host B.

[DeviceB-security-policy-ip] rule name untrust-trust

[DeviceB-security-policy-ip-4-untrust-trust] source-zone untrust

[DeviceB-security-policy-ip-4-untrust-trust] destination-zone trust

[DeviceB-security-policy-ip-4-untrust-trust] source-ip-subnet 10.1.1.0 24

[DeviceB-security-policy-ip-4-untrust-trust] destination-ip-subnet 10.1.2.0 24

[DeviceB-security-policy-ip-4-untrust-trust] action pass

[DeviceB-security-policy-ip-4-untrust-trust] quit

[DeviceB-security-policy-ip] quit

5.        Define the data flows to be protected:

# Configure IPv4 advanced ACL 3101 to identify traffic from subnet 10.1.2.0/24 to subnet 10.1.1.0/24.

[DeviceA] acl advanced 3101

[DeviceA-acl-ipv4-adv-3101] rule 0 permit ip source 10.1.2.0 0.0.0.255 destination 10.1.1.0 0.0.0.255

[DeviceA-acl-ipv4-adv-3101] quit

6.        Configure an IPsec transform set to specify the packet encapsulation mode, security protocols, and algorithms.

The IPsec transform set settings at both sides of the IPsec tunnel must be the same.

<DeviceB> system-view

[DeviceB] ipsec transform-set transform1

[DeviceB-ipsec-transform-set-transform1] protocol esp

[DeviceB-ipsec-transform-set-transform1] esp encryption-algorithm 3des-cbc

[DeviceB-ipsec-transform-set-transform1] esp authentication-algorithm md5

[DeviceB-ipsec-transform-set-transform1] quit

7.        Configure an IKEv2 keychain to specify the key information used by both sides of the IKE communication.

[DeviceB]ikev2 keychain keychain1

[DeviceB-ikev2-keychain-keychain1] peer peer1

[DeviceB-ikev2-keychain-keychain1-peer-peer1] address 3.3.3.1 16

[DeviceB-ikev2-keychain-keychain1-peer-peer1] identity address 3.3.3.1

[DeviceB-ikev2-keychain-keychain1-peer-peer1] pre-shared-key plaintext 123

[DeviceB-ikev2-keychain-keychain1-peer-peer1] quit

[DeviceB-ikev2-keychain-keychain1] quit

8.        Configure an IKEv2 profile to specify the security parameters used for setting up IKE SAs.

[DeviceB] ikev2 profile profile1

[DeviceB-ikev2-profile-profile1] keychain keychain1

[DeviceB-ikev2-profile-profile1] match remote identity fqdn www.devicea.com

[DeviceB-ikev2-profile-profile1] authentication-method local pre-share

[DeviceB-ikev2-profile-profile1] authentication-method remote pre-share

[DeviceB-ikev2-profile-profile1] quit

9.        Configure an IPsec policy template, which is used to create an IPsec policy.

[DeviceB] ipsec policy-template template1 1

[DeviceB-ipsec-policy-template-template1-1] remote-address 3.3.3.1

[DeviceB-ipsec-policy-template-template1-1] security acl 3101

[DeviceB-ipsec-policy-template-template1-1] transform-set transform1

[DeviceB-ipsec-policy-template-template1-1] ikev2-profile profile1

[DeviceB-ipsec-policy-template-template1-1] quit

10.     Create an IKE-based IPsec policy entry by using IPsec policy template, so as to establish an IPsec tunnel to protect the specified data flow.

[DeviceB] ipsec policy policy1 1 isakmp template template1

11.     Apply the IPsec policy to GigabitEthernet 1/0/1 to protect the traffic on the interface.

[DeviceB] interface gigabitethernet 1/0/1

[DeviceB-GigabitEthernet1/0/1] ipsec apply policy policy1

[DeviceB-GigabitEthernet1/0/1] quit

Verifying the configuration

# Initiate a connection from subnet 10.1.1.0/24 to subnet 10.1.2.0/24 to trigger IKEv2 negotiation. After IPsec SAs are successfully negotiated by IKEv2, traffic between the two subnets is IPsec-protected.

# Display the IKEv2 SA on Device A.

[DeviceA] display ikev2 sa

Tunnel ID   Local                       Remote                      Status

---------------------------------------------------------------------------

  1        1.1.1.1/4500                  2.2.2.2/4500                  EST

Status:

IN-NEGO: Negotiating, EST: Established, DEL:Deleting

 [DeviceA] display ikev2 sa verbose

  Tunnel ID: 45                                                                

  Local IP/Port: 1.1.1.1/4500                                                   

  Remote IP/Port: 2.2.2.2/4500                                                 

  Outside VRF: -                                                               

  Inside VRF: -                                                                 

  Local SPI: 372228d699a33c63                                                  

  Remote SPI: 75c537621b4a7190                                                 

                                                                               

  Local ID type: ID_FQDN                                                       

  Local ID: www.devicea.com                                                    

  Remote ID type: ID_IPV4_ADDR                                                 

  Remote ID: 2.2.2.2                                                            

                                                                               

  Auth sign method: Pre-shared key                                             

  Auth verify method: Pre-shared key                                           

  Integrity algorithm: SHA1                                                    

  PRF algorithm: SHA1                                                          

  Encryption algorithm: AES-CBC-128                                             

                                                                               

  Life duration: 86400 secs                                                    

  Remaining key duration: 86177 secs                                            

  Diffie-Hellman group: MODP1536/Group5                                        

  NAT traversal: Detected                                                      

  DPD: Interval 0 secs, retry interval 0 secs                                  

  Transmitting entity: Initiator                                               

                                                                               

  Local window: 1                                                              

  Remote window: 1                                                             

  Local request message ID: 2                                                  

  Remote request message ID: 0                                                 

  Local next message ID: 2                                                     

  Remote next message ID: 0   

# Display the IPsec SAs on Device A.

[DeviceA] display ipsec sa

-------------------------------

Interface: GigabitEthernet1/0/1

-------------------------------

 

  -----------------------------

  IPsec policy: policy1

  Sequence number: 1

  Mode: ISAKMP

  -----------------------------

    Tunnel id: 0

    Encapsulation mode: tunnel

    Perfect Forward Secrecy:

    Inside VPN:                                                                

    Extended Sequence Numbers enable: N                                        

    Traffic Flow Confidentiality enable: N

    Path MTU: 1435

    Tunnel:

        local  address/port: 1.1.1.1/500

        remote address/port: 2.2.2.2/500

    Flow:

        sour addr: 10.1.1.0/255.255.255.0  port: 0  protocol: ip

        dest addr: 10.2.1.0/255.255.255.0  port: 0  protocol: ip

 

    [Inbound ESP SAs]

      SPI: 830667426 (0x3182faa2)

      Connection ID: 605590388736

      Transform set: ESP-ENCRYPT-3DES-CBC ESP-AUTH-MD5

      SA duration (kilobytes/sec): 1843200/3600

      SA remaining duration (kilobytes/sec): 1843200/2313

      Max received sequence-number:

      Anti-replay check enable: Y

      Anti-replay window size: 64

      UDP encapsulation used for NAT traversal: Y

      Status: Active

 

    [Outbound ESP SAs]

      SPI: 3516214669 (0xd1952d8d)

      Connection ID: 227633266689

      Transform set: ESP-ENCRYPT-3DES-CBC ESP-AUTH-MD5

      SA duration (kilobytes/sec): 1843200/3600

      SA remaining duration (kilobytes/sec): 1843200/2313

      Max sent sequence-number:

      UDP encapsulation used for NAT traversal: Y

      Status: Active

Configuration files

#

interface GigabitEthernet1/0/1

 ip address 1.1.1.1 255.255.0.0

 ipsec apply policy policy1

#

interface GigabitEthernet1/0/2

 ip address 10.1.1.1 255.255.255.0

#

security-zone name Trust

 import interface GigabitEthernet1/0/2

#

security-zone name Untrust

 import interface GigabitEthernet1/0/1

#

 ip route-static 2.2.0.0 16 1.1.1.2

 ip route-static 10.1.2.0 24 1.1.1.2

#

acl advanced 3101

 rule 0 permit ip source 10.1.1.0 0.0.0.255 destination 10.1.2.0 0.0.0.255

#

ipsec transform-set transform1

 encapsulation-mode tunnel

 protocol esp

 esp encryption-algorithm 3des-cbc

 esp authentication-algorithm md5

#

ipsec policy policy1 1 isakmp

 transform-set transform1

 security acl 3101

 remote-address 2.2.2.2

 ikev2-profile profile1

#

ikev2 keychain keychain1

 peer peer1

  address 2.2.2.2 255.255.0.0

  identity address 2.2.2.2

  pre-shared-key plaintext 123

#

ikev2 profile profile1

 authentication-method local pre-share

 authentication-method remote pre-share

 keychain keychain1

 identity local fqdn www.devicea.com

 match remote identity address 2.2.2.2 255.255.0.0

#

security-policy ip

 rule 0 name ipseclocalout

  action pass

  source-zone local

  destination-zone untrust

  source-ip-host 1.1.1.1

  destination-ip-host 2.2.2.2

 rule 1 name ipseclocalin

  action pass

  source-zone untrust

  destination-zone local

  source-ip-host 2.2.2.2

  destination-ip-host 1.1.1.1

 rule 2 name trust-untrust

  action pass

  source-zone trust

  destination-zone untrust

  source-ip-subnet 10.1.1.0 255.255.255.0

  destination-ip-subnet 10.1.2.0 255.255.255.0

 rule 3 name untrust-trust

  action pass

  source-zone untrust

  destination-zone trust

  source-ip-subnet 10.1.2.0 255.255.255.0

  destination-ip-subnet 10.1.1.0 255.255.255.0

#

#

interface GigabitEthernet1/0/1

 ip address 2.2.2.2 255.255.0.0

 ipsec apply policy policy1

#

interface GigabitEthernet1/0/2

 ip address 10.1.2.1 255.255.255.0

#

security-zone name Trust

 import interface GigabitEthernet1/0/2

#

security-zone name Untrust

 import interface GigabitEthernet1/0/1

#

 ip route-static 1.1.0.0 16 2.2.2.1

 ip route-static 10.1.1.0 24 2.2.2.1

#

acl advanced 3101

 rule 0 permit ip source 10.1.2.0 0.0.0.255 destination 10.1.1.0 0.0.0.255

#

ipsec transform-set transform1

 encapsulation-mode tunnel

 protocol esp

 esp encryption-algorithm 3des-cbc

 esp authentication-algorithm md5

#

ipsec policy-template template1 1

 transform-set transform1

 security acl 3101

 remote-address 3.3.3.1

 ikev2-profile profile1

#

ipsec policy policy1 1 isakmp template template1

#

ikev2 keychain keychain1

 peer peer1

  address 3.3.3.1 255.255.0.0

  identity address 3.3.3.1

  pre-shared-key plaintext 123

#

ikev2 profile profile1

 authentication-method local pre-share

 authentication-method remote pre-share

 keychain keychain1

 match remote identity fqdn www.devicea.com

#

security-policy ip

 rule 0 name ipseclocalout

  action pass

  source-zone local

  destination-zone untrust

  source-ip-host 2.2.2.2

  destination-ip-host 3.3.3.1

 rule 1 name ipseclocalin

  action pass

  source-zone untrust

  destination-zone local

  source-ip-host 3.3.3.1

  destination-ip-host 2.2.2.2

 rule 2 name trust-untrust

  action pass

  source-zone trust

  destination-zone untrust

  source-ip-subnet 10.1.2.0 255.255.255.0

  destination-ip-subnet 10.1.1.0 255.255.255.0

 rule 3 name untrust-trust

  action pass

  source-zone untrust

  destination-zone trust

  source-ip-subnet 10.1.1.0 255.255.255.0

  destination-ip-subnet 10.1.2.0 255.255.255.0

#