NDP proxy

If NDP proxy is set on a router, it is used to publish IPv6 addresses to external routers. Its purpose is similar to floating IP, but it forwards the traffic directly by using route rules and has no NAT action. Read the related specification for more details.

Configuration of NDP proxy

To configure NDP proxy, take the following steps:

  • On the controller nodes:

    Add the ndp_proxy service to the service_plugins setting in the [DEFAULT] section of /etc/neutron/neutron.conf. For example:

    [DEFAULT]
    service_plugins = router,ndp_proxy
    

    Note

    The router service plug-in has to be configured along with the ndp_proxy service plug-in.

  • On the network nodes or the compute nodes (for the dvr mode router):

    Set the extensions option in the [agent] section of /etc/neutron/l3_agent.ini to include ndp_proxy. This has to be done in each network and compute node where the L3 agent is running. For example:

    extensions = ndp_proxy
    

Note

After updating the options in the configuration files, the neutron-server and every neutron-l3-agent need to be restarted for the new values to take effect.

After configuring NDP proxy, the ndp-proxy extension alias will be included in the output of the following command:

For API extension:

$ openstack extension list --network

For agent extension:

$ openstack network agent show <l3-agent-id>

Note

We introduced a new command ndsend for the NDP proxy feature, the command can send Neighbor Advertisement about IPv6 to upstream router. With this command, we can make the upstream router rapidly perceive the change of internal IPv6 address (such as, port migrated to other node). Read the manual page for more details about this command.

Currently, you need to install this command manually in every L3 agent node. For Ubuntu, the command is provided by the vzctl pkg, the install command: sudo apt install vzctl.

  • On the upstream router (the datacenter’s physical router):

    Generally, the admin operator should plan one or more IPv6 subnetpools to use when NDP proxy is enabled, so that all internal subnets can be allocated from a single, integrated subnetpool. In order to make NDP proxy work correctly, the admin operator needs to set direct routes for these subnetpools.

    Such as, we have a IPv6 subnetpool, it’s CIDR is 2001:db8::/96. The direct route like below should be set:

    2001:db8::/96 dev <ext-gw>
    

    The ext-gw is the gateway interface of the cloud’s external network.

User workflow

The basic steps to publish an IPv6 address to an external network (such as: public network) are the following:

Note

In order to prevent a potential security risk, the NDP proxy feature requires that an IPv6 address scope be used to ensure the uniqueness of the IPv6 address which is published externally.

  1. Create an IPv6 address scope

    $ openstack address scope create test-ipv6-as --ip-version 6
    +------------+--------------------------------------+
    | Field      | Value                                |
    +------------+--------------------------------------+
    | id         | 24761ec5-b659-4358-b9ab-495ead15fa7a |
    | ip_version | 6                                    |
    | name       | test-ipv6-as                         |
    | project_id | bcb0c7a5338b4a46959e47971c58f0f1     |
    | shared     | False                                |
    +------------+--------------------------------------+
    
  2. Create an IPv6 subnet pool

    $ openstack subnet pool create test-subnetpool --address-scope test-ipv6-as \
            --pool-prefix 2001:db8::/96 --default-prefix-length 112
    +-------------------+--------------------------------------+
    | Field             | Value                                |
    +-------------------+--------------------------------------+
    | address_scope_id  | 24761ec5-b659-4358-b9ab-495ead15fa7a |
    | created_at        | 2022-09-05T06:16:31Z                 |
    | default_prefixlen | 112                                  |
    | default_quota     | None                                 |
    | description       |                                      |
    | id                | 4af07f59-45b8-424d-98c5-35d20ba61526 |
    | ip_version        | 6                                    |
    | is_default        | False                                |
    | max_prefixlen     | 128                                  |
    | min_prefixlen     | 64                                   |
    | name              | test-subnetpool                      |
    | prefixes          | 2001:db8::/96                        |
    | project_id        | bcb0c7a5338b4a46959e47971c58f0f1     |
    | revision_number   | 0                                    |
    | shared            | False                                |
    | tags              |                                      |
    | updated_at        | 2022-01-01T06:42:08Z                 |
    +-------------------+--------------------------------------+
    
  3. Create an external network

    $ openstack network create --external --provider-network-type flat \
          --provider-physical-network public public
    +---------------------------+--------------------------------------+
    | Field                     | Value                                |
    +---------------------------+--------------------------------------+
    | admin_state_up            | UP                                   |
    | availability_zone_hints   |                                      |
    | availability_zones        |                                      |
    | created_at                | 2022-09-05T06:18:31Z                 |
    | description               |                                      |
    | dns_domain                | None                                 |
    | id                        | 98b0f468-7be0-4530-919d-c4d9417c3abf |
    | ipv4_address_scope        | None                                 |
    | ipv6_address_scope        | None                                 |
    | is_default                | False                                |
    | is_vlan_transparent       | None                                 |
    | mtu                       | 1500                                 |
    | name                      | public                               |
    | port_security_enabled     | True                                 |
    | project_id                | bcb0c7a5338b4a46959e47971c58f0f1     |
    | provider:network_type     | flat                                 |
    | provider:physical_network | public                               |
    | provider:segmentation_id  | None                                 |
    | qos_policy_id             | None                                 |
    | revision_number           | 1                                    |
    | router:external           | External                             |
    | segments                  | None                                 |
    | shared                    | False                                |
    | status                    | ACTIVE                               |
    | subnets                   |                                      |
    | tags                      |                                      |
    | updated_at                | 2022-01-01T06:45:08Z                 |
    +---------------------------+--------------------------------------+
    
  4. Create an external subnet

    $ openstack subnet create --network public --subnet-pool test-subnetpool \
            --prefix-length 112 --ip-version 6 --no-dhcp ext-sub
     +----------------------+--------------------------------------+
    | Field                | Value                                |
    +----------------------+--------------------------------------+
    | allocation_pools     | 2001:db8::2-2001:db8::ffff           |
    | cidr                 | 2001:db8::/112                       |
    | created_at           | 2022-09-05T06:21:37Z                 |
    | description          |                                      |
    | dns_nameservers      |                                      |
    | dns_publish_fixed_ip | None                                 |
    | enable_dhcp          | False                                |
    | gateway_ip           | 2001:db8::1                          |
    | host_routes          |                                      |
    | id                   | ec11de28-9b84-4cee-b6a1-0ed56135bcd8 |
    | ip_version           | 6                                    |
    | ipv6_address_mode    | None                                 |
    | ipv6_ra_mode         | None                                 |
    | name                 | ext-sub                              |
    | network_id           | 98b0f468-7be0-4530-919d-c4d9417c3abf |
    | project_id           | bcb0c7a5338b4a46959e47971c58f0f1     |
    | revision_number      | 0                                    |
    | segment_id           | None                                 |
    | service_types        |                                      |
    | subnetpool_id        | 4af07f59-45b8-424d-98c5-35d20ba61526 |
    | tags                 |                                      |
    | updated_at           | 2022-01-01T06:47:08Z                 |
    +----------------------+--------------------------------------+
    
  5. Create a router:

    $ openstack router create test-router
    +-------------------------+--------------------------------------+
    | Field                   | Value                                |
    +-------------------------+--------------------------------------+
    | admin_state_up          | UP                                   |
    | availability_zone_hints |                                      |
    | availability_zones      |                                      |
    | created_at              | 2022-01-01T06:50:44Z                 |
    | description             |                                      |
    | distributed             | False                                |
    | enable_ndp_proxy        | False                                |
    | external_gateway_info   | null                                 |
    | flavor_id               | None                                 |
    | ha                      | False                                |
    | id                      | 3aab8554-e5c4-4262-ab95-b92857c641de |
    | name                    | test-router                          |
    | project_id              | bcb0c7a5338b4a46959e47971c58f0f1     |
    | revision_number         | 1                                    |
    | routes                  |                                      |
    | status                  | ACTIVE                               |
    | tags                    |                                      |
    | updated_at              | 2022-01-01T06:50:44Z                 |
    +-------------------------+--------------------------------------+
    
  6. Set external gateway for the router:

    $ openstack router set test-router --external-gateway public
    

    Note

    If the external network has no IPv6 subnet and the ipv6_gateway is configured on the neutron-l3-agent, you may want to set use_lla_address to True at /etc/neutron/neutron.conf, otherwise the following command will raise a 403 error.

  7. Enable NDP proxy support on the router:

    $ openstack router set test-router --enable-ndp-proxy
    

    Warning

    If you are using another method (such as: BGP, Prefix delegation etc.) to publish the internal IPv6 address, the command will break dataplane traffic.

  8. Create an internal network and IPv6 subnet and add the subnet to the above router:

    $ openstack network create int-net
    +---------------------------+--------------------------------------+
    | Field                     | Value                                |
    +---------------------------+--------------------------------------+
    | admin_state_up            | UP                                   |
    | availability_zone_hints   |                                      |
    | availability_zones        |                                      |
    | created_at                | 2022-01-01T07:11:08Z                 |
    | description               |                                      |
    | dns_domain                | None                                 |
    | id                        | e527b38e-9e2a-439b-adf8-4ee1aa4f03b1 |
    | ipv4_address_scope        | None                                 |
    | ipv6_address_scope        | None                                 |
    | is_default                | False                                |
    | is_vlan_transparent       | None                                 |
    | mtu                       | 1450                                 |
    | name                      | int-net                              |
    | port_security_enabled     | True                                 |
    | project_id                | bcb0c7a5338b4a46959e47971c58f0f1     |
    | provider:network_type     | vxlan                                |
    | provider:physical_network | None                                 |
    | provider:segmentation_id  | 575                                  |
    | qos_policy_id             | None                                 |
    | revision_number           | 1                                    |
    | router:external           | Internal                             |
    | segments                  | None                                 |
    | shared                    | False                                |
    | status                    | ACTIVE                               |
    | subnets                   |                                      |
    | tags                      |                                      |
    | updated_at                | 2022-01-01T07:11:08Z                 |
    +---------------------------+--------------------------------------+
    $ openstack subnet create --network int-net --subnet-pool test-subnetpool \
      --prefix-length 112 --ip-version 6 \
      --ipv6-ra-mode dhcpv6-stateful \
      --ipv6-address-mode dhcpv6-stateful int-sub
    +----------------------+--------------------------------------+
    | Field                | Value                                |
    +----------------------+--------------------------------------+
    | allocation_pools     | 2001:db8::1:2-2001:db8::1:ffff       |
    | cidr                 | 2001:db8::1:0/112                    |
    | created_at           | 2022-09-05T06:24:13Z                 |
    | description          |                                      |
    | dns_nameservers      |                                      |
    | dns_publish_fixed_ip | None                                 |
    | enable_dhcp          | True                                 |
    | gateway_ip           | 2001:db8::1:1                        |
    | host_routes          |                                      |
    | id                   | 9bcf194c-d44f-4e6f-90da-98510ddef283 |
    | ip_version           | 6                                    |
    | ipv6_address_mode    | dhcpv6-stateful                      |
    | ipv6_ra_mode         | dhcpv6-stateful                      |
    | name                 | int-sub                              |
    | network_id           | e527b38e-9e2a-439b-adf8-4ee1aa4f03b1 |
    | project_id           | bcb0c7a5338b4a46959e47971c58f0f1     |
    | revision_number      | 0                                    |
    | segment_id           | None                                 |
    | service_types        |                                      |
    | subnetpool_id        | 4af07f59-45b8-424d-98c5-35d20ba61526 |
    | tags                 |                                      |
    | updated_at           | 2022-01-02T08:20:26Z                 |
    +----------------------+--------------------------------------+
    $ openstack router add subnet test-router int-sub
    
  9. Launch an instance:

    $ openstack server create --flavor m1.tiny --image cirros-0.5.2-x86_64-disk --network int-net test-server
    +-------------------------------------+-----------------------------------------------------------------+
    | Field                               | Value                                                           |
    +-------------------------------------+-----------------------------------------------------------------+
    | OS-DCF:diskConfig                   | MANUAL                                                          |
    | OS-EXT-AZ:availability_zone         |                                                                 |
    | OS-EXT-SRV-ATTR:host                | None                                                            |
    | OS-EXT-SRV-ATTR:hypervisor_hostname | None                                                            |
    | OS-EXT-SRV-ATTR:instance_name       |                                                                 |
    | OS-EXT-STS:power_state              | NOSTATE                                                         |
    | OS-EXT-STS:task_state               | scheduling                                                      |
    | OS-EXT-STS:vm_state                 | building                                                        |
    | OS-SRV-USG:launched_at              | None                                                            |
    | OS-SRV-USG:terminated_at            | None                                                            |
    | accessIPv4                          |                                                                 |
    | accessIPv6                          |                                                                 |
    | addresses                           |                                                                 |
    | adminPass                           | 97UvRLgdFozR                                                    |
    | config_drive                        |                                                                 |
    | created                             | 2022-01-02T08:22:35Z                                            |
    | flavor                              | m1.tiny (1)                                                     |
    | hostId                              |                                                                 |
    | id                                  | 189a104c-36cd-479a-8702-8111eb34fdb6                            |
    | image                               | cirros-0.5.2-x86_64-disk (2b2d2975-7ffc-463b-8c0e-993122f38b77) |
    | key_name                            | None                                                            |
    | name                                | test-server                                                     |
    | progress                            | 0                                                               |
    | project_id                          | bcb0c7a5338b4a46959e47971c58f0f1                                |
    | properties                          |                                                                 |
    | security_groups                     | name='default'                                                  |
    | status                              | BUILD                                                           |
    | updated                             | 2022-01-02T08:22:34Z                                            |
    | user_id                             | 27e0947bb4fe47e4981da31d4a18ddf7                                |
    | volumes_attached                    |                                                                 |
    +-------------------------------------+-----------------------------------------------------------------+
    
  10. Create NDP proxy for the instance’s port:

    Query the port of the instance

    $ openstack port list --server test-server
    +--------------------------------------+------+-------------------+--------------------------------------------------------------------------------+--------+
    | ID                                   | Name | MAC Address       | Fixed IP Addresses                                                             | Status |
    +--------------------------------------+------+-------------------+--------------------------------------------------------------------------------+--------+
    | bdd64aa0-437a-4db6-bbca-99869426c908 |      | fa:16:3e:ac:15:b8 | ip_address='2001:db8::1:284', subnet_id='9bcf194c-d44f-4e6f-90da-98510ddef283' | ACTIVE |
    +--------------------------------------+------+-------------------+--------------------------------------------------------------------------------+--------+
    

    Create NDP proxy for the port

    $ openstack router ndp proxy create test-router --port bdd64aa0-437a-4db6-bbca-99869426c908 --name test-np
    +-----------------+--------------------------------------+
    | Field           | Value                                |
    +-----------------+--------------------------------------+
    | created_at      | 2022-01-02T08:25:31Z                 |
    | description     |                                      |
    | id              | 73889fee-e322-443f-941e-142e4fc5f898 |
    | ip_address      | 2001:db8::1:284                      |
    | name            | test-np                              |
    | port_id         | bdd64aa0-437a-4db6-bbca-99869426c908 |
    | project_id      | bcb0c7a5338b4a46959e47971c58f0f1     |
    | revision_number | 0                                    |
    | router_id       | 3aab8554-e5c4-4262-ab95-b92857c641de |
    | updated_at      | 2022-01-02T08:25:31Z                 |
    +-----------------+--------------------------------------+
    
  11. Then ping the port’s address from the upstream router:

    $ ping 2001:db8::1:284
    PING 2001:db8::1:284(2001:db8::1:284) 56 data bytes
    64 bytes from 2001:db8::1:284: icmp_seq=1 ttl=64 time=0.365 ms
    64 bytes from 2001:db8::1:284: icmp_seq=2 ttl=64 time=0.385 ms
    

    Note

    You may also need to add a security group rule that allows ICMPv6 traffic towards the instance.

Known limitations

  • Using NDP proxies in combination with the OVN backend is not supported.