:lastproofread: 2021-06-28

.. _examples-azure-vpn-dual-bgp:

Route-Based Redundant Site-to-Site VPN to Azure (BGP over IKEv2/IPsec)
----------------------------------------------------------------------

This guide shows an example of a redundant (active-active) route-based IKEv2
site-to-site VPN to Azure using VTI
and BGP for dynamic routing updates.

Prerequisites
^^^^^^^^^^^^^

- A pair of Azure VNet Gateways deployed in active-active
  configuration with BGP enabled.

- A local network gateway deployed in Azure representing
  the Vyos device, matching the below Vyos settings except for
  address space, which only requires the Vyos private IP, in
  this example 10.10.0.5/32

- A connection resource deployed in Azure linking the
  Azure VNet gateway and the local network gateway representing
  the Vyos device.

Example
^^^^^^^

+---------------------------------------+---------------------+
| WAN Interface                         | eth0                |
+---------------------------------------+---------------------+
| On-premises address space             | 10.10.0.0/16        |
+---------------------------------------+---------------------+
| Azure address space                   |  10.0.0.0/16        |
+---------------------------------------+---------------------+
| Vyos public IP                        | 198.51.100.3        |
+---------------------------------------+---------------------+
| Vyos private IP                       | 10.10.0.5           |
+---------------------------------------+---------------------+
| Azure VNet Gateway 1 public IP        |  203.0.113.2        |
+---------------------------------------+---------------------+
| Azure VNet Gateway 2 public IP        |  203.0.113.3        |
+---------------------------------------+---------------------+
| Azure VNet Gateway BGP IP             |  10.0.0.4,10.0.0.5  |
+---------------------------------------+---------------------+
| Pre-shared key                        | ch00s3-4-s3cur3-psk |
+---------------------------------------+---------------------+
| Vyos ASN                              | 64499               |
+---------------------------------------+---------------------+
| Azure ASN                             | 65540               |
+---------------------------------------+---------------------+

Vyos configuration
^^^^^^^^^^^^^^^^^^

- Configure the IKE and ESP settings to match a subset
  of those supported by Azure:

.. code-block:: none

  set vpn ipsec esp-group AZURE compression 'disable'
  set vpn ipsec esp-group AZURE lifetime '3600'
  set vpn ipsec esp-group AZURE mode 'tunnel'
  set vpn ipsec esp-group AZURE pfs 'dh-group2'
  set vpn ipsec esp-group AZURE proposal 1 encryption 'aes256'
  set vpn ipsec esp-group AZURE proposal 1 hash 'sha1'

  set vpn ipsec ike-group AZURE dead-peer-detection action 'restart'
  set vpn ipsec ike-group AZURE dead-peer-detection interval '15'
  set vpn ipsec ike-group AZURE dead-peer-detection timeout '30'
  set vpn ipsec ike-group AZURE ikev2-reauth 'yes'
  set vpn ipsec ike-group AZURE key-exchange 'ikev2'
  set vpn ipsec ike-group AZURE lifetime '28800'
  set vpn ipsec ike-group AZURE proposal 1 dh-group '2'
  set vpn ipsec ike-group AZURE proposal 1 encryption 'aes256'
  set vpn ipsec ike-group AZURE proposal 1 hash 'sha1'

- Enable IPsec on eth0

.. code-block:: none

  set vpn ipsec interface 'eth0'

- Configure two VTIs with a dummy IP address each

.. code-block:: none

  set interfaces vti vti1 address '10.10.1.5/32'
  set interfaces vti vti1 description 'Azure Primary Tunnel'

  set interfaces vti vti2 address '10.10.1.6/32'
  set interfaces vti vti2 description 'Azure Secondary Tunnel'

- Clamp the VTI's MSS to 1350 to avoid PMTU blackholes.

.. code-block:: none

  set firewall options interface vti1 adjust-mss 1350
  set firewall options interface vti2 adjust-mss 1350

- Configure the VPN tunnels

.. code-block:: none

  set vpn ipsec authentication psk azure id '198.51.100.3'
  set vpn ipsec authentication psk azure id '203.0.113.2'
  set vpn ipsec authentication psk azure id '203.0.113.3'
  set vpn ipsec authentication psk azure secret 'ch00s3-4-s3cur3-psk'

  set vpn ipsec site-to-site peer azure-primary authentication local-id '198.51.100.3'
  set vpn ipsec site-to-site peer azure-primary authentication mode 'pre-shared-secret'
  set vpn ipsec site-to-site peer azure-primary authentication remote-id '203.0.113.2'
  set vpn ipsec site-to-site peer azure-primary connection-type 'respond'
  set vpn ipsec site-to-site peer azure-primary description 'AZURE PRIMARY TUNNEL'
  set vpn ipsec site-to-site peer azure-primary ike-group 'AZURE'
  set vpn ipsec site-to-site peer azure-primary ikev2-reauth 'inherit'
  set vpn ipsec site-to-site peer azure-primary local-address '10.10.0.5'
  set vpn ipsec site-to-site peer azure-primary remote-address '203.0.113.2'
  set vpn ipsec site-to-site peer azure-primary vti bind 'vti1'
  set vpn ipsec site-to-site peer azure-primary vti esp-group 'AZURE'

  set vpn ipsec site-to-site peer azure-secondary authentication local-id '198.51.100.3'
  set vpn ipsec site-to-site peer azure-secondary authentication mode 'pre-shared-secret'
  set vpn ipsec site-to-site peer azure-secondary authentication remote-id '203.0.113.3'
  set vpn ipsec site-to-site peer azure-secondary connection-type 'respond'
  set vpn ipsec site-to-site peer azure-secondary description 'AZURE secondary TUNNEL'
  set vpn ipsec site-to-site peer azure-secondary ike-group 'AZURE'
  set vpn ipsec site-to-site peer azure-secondary ikev2-reauth 'inherit'
  set vpn ipsec site-to-site peer azure-secondary local-address '10.10.0.5'
  set vpn ipsec site-to-site peer azure-secondary remote-address '203.0.113.3'
  set vpn ipsec site-to-site peer azure-secondary vti bind 'vti2'
  set vpn ipsec site-to-site peer azure-secondary vti esp-group 'AZURE'

- **Important**: Add an interface route to reach both Azure's BGP listeners

.. code-block:: none

  set protocols static route 10.0.0.4/32 interface vti1
  set protocols static route 10.0.0.5/32 interface vti2

- Configure your BGP settings

.. code-block:: none

  set protocols bgp system-as 64499
  set protocols bgp neighbor 10.0.0.4 remote-as '65540'
  set protocols bgp neighbor 10.0.0.4 address-family ipv4-unicast soft-reconfiguration 'inbound'
  set protocols bgp neighbor 10.0.0.4 timers holdtime '30'
  set protocols bgp neighbor 10.0.0.4 timers keepalive '10'

  set protocols bgp neighbor 10.0.0.5 remote-as '65540'
  set protocols bgp neighbor 10.0.0.5 address-family ipv4-unicast soft-reconfiguration 'inbound'
  set protocols bgp neighbor 10.0.0.5 timers holdtime '30'
  set protocols bgp neighbor 10.0.0.5 timers keepalive '10'

- **Important**: Disable connected check, otherwise the routes learned
  from Azure will not be imported into the routing table.

.. code-block:: none

  set protocols bgp neighbor 10.0.0.4 disable-connected-check
  set protocols bgp neighbor 10.0.0.5 disable-connected-check