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diff --git a/docs/vpn/l2tp.rst b/docs/vpn/l2tp.rst new file mode 100644 index 00000000..0dd5fe3e --- /dev/null +++ b/docs/vpn/l2tp.rst @@ -0,0 +1,237 @@ +.. _l2tp: + +L2TP +----------- + +VyOS utilizes accel-ppp_ to provide SSTP server functionality. It can be used +with local authentication or a connected RADIUS server. + +L2TP over IPsec +=============== + +Example for configuring a simple L2TP over IPsec VPN for remote access (works +with native Windows and Mac VPN clients): + +.. code-block:: sh + + set vpn ipsec ipsec-interfaces interface eth0 + set vpn ipsec nat-traversal enable + set vpn ipsec nat-networks allowed-network 0.0.0.0/0 + + set vpn l2tp remote-access outside-address 192.0.2.2 + set vpn l2tp remote-access outside-nexthop 192.168.255.1 + set vpn l2tp remote-access client-ip-pool start 192.168.255.2 + set vpn l2tp remote-access client-ip-pool stop 192.168.255.254 + set vpn l2tp remote-access ipsec-settings authentication mode pre-shared-secret + set vpn l2tp remote-access ipsec-settings authentication pre-shared-secret <secret> + set vpn l2tp remote-access authentication mode local + set vpn l2tp remote-access authentication local-users username test password 'test' + +In the example above an external IP of 192.0.2.2 is assumed. Nexthop IP address +192.168.255.1 uses as client tunnel termination point. + +If a local firewall policy is in place on your external interface you will need +to allow the ports below: + +* UDP port 500 (IKE) +* IP protocol number 50 (ESP) +* UDP port 1701 for IPsec + +As well as the below to allow NAT-traversal: + +* UDP port 4500 (NAT-T) + +Example: + +.. code-block:: sh + + set firewall name OUTSIDE-LOCAL rule 40 action 'accept' + set firewall name OUTSIDE-LOCAL rule 40 protocol 'esp' + set firewall name OUTSIDE-LOCAL rule 41 action 'accept' + set firewall name OUTSIDE-LOCAL rule 41 destination port '500' + set firewall name OUTSIDE-LOCAL rule 41 protocol 'udp' + set firewall name OUTSIDE-LOCAL rule 42 action 'accept' + set firewall name OUTSIDE-LOCAL rule 42 destination port '4500' + set firewall name OUTSIDE-LOCAL rule 42 protocol 'udp' + set firewall name OUTSIDE-LOCAL rule 43 action 'accept' + set firewall name OUTSIDE-LOCAL rule 43 destination port '1701' + set firewall name OUTSIDE-LOCAL rule 43 ipsec 'match-ipsec' + set firewall name OUTSIDE-LOCAL rule 43 protocol 'udp' + +To allow VPN-clients access via your external address, a NAT rule is required: + + +.. code-block:: sh + + set nat source rule 110 outbound-interface 'eth0' + set nat source rule 110 source address '192.168.255.0/24' + set nat source rule 110 translation address masquerade + + +VPN-clients will request configuration parameters, optionally you can DNS +parameter to the client. + +.. code-block:: sh + + set vpn l2tp remote-access dns-servers server-1 '8.8.8.8' + set vpn l2tp remote-access dns-servers server-2 '8.8.4.4' + +.. note:: Those are the `Google public DNS`_ servers. You can also use the + public available servers from Quad9_ (9.9.9.9) or Cloudflare_ (1.1.1.1). + +Established sessions can be viewed using the **show vpn remote-access** +operational command, or **show l2tp-server sessions** + +.. code-block:: sh + + vyos@vyos:~$ show vpn remote-access + ifname | username | calling-sid | ip | rate-limit | type | comp | state | uptime + --------+----------+--------------+---------------+------------+------+------+--------+---------- + ppp0 | vyos | 192.168.0.36 | 192.168.255.1 | | l2tp | | active | 00:06:13 + + +LNS (L2TP Network Server) +========================= + +LNS are often used to connect to a LAC (L2TP Access Concentrator). + +Below is an example to configure a LNS: + +.. code-block:: sh + + set vpn l2tp remote-access outside-address 192.0.2.2 + set vpn l2tp remote-access outside-nexthop 192.168.255.1 + set vpn l2tp remote-access client-ip-pool start 192.168.255.2 + set vpn l2tp remote-access client-ip-pool stop 192.168.255.254 + set vpn l2tp remote-access lns shared-secret 'secret' + set vpn l2tp remote-access ccp-disable + set vpn l2tp remote-access authentication mode local + set vpn l2tp remote-access authentication local-users username test password 'test' + +The example above uses 192.0.2.2 as external IP address, the nexthop is supposed +to be 192.168.255.1 and is used as client termination point. A LAC normally +requires an authentication password, which is set in the example configuration +to ``lns shared-secret 'secret'``. This setup requires the Compression Control +Protocol (CCP) being disabled, the command ``set vpn l2tp remote-access ccp-disable`` +accomplishes that. + + +Bandwidth Shaping +================= + +Bandwidth rate limits can be set for local users or via RADIUS based attributes. + +Bandwidth Shaping for local users +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The rate-limit is set in kbit/sec. + +.. code-block:: sh + + set vpn l2tp remote-access outside-address 192.0.2.2 + set vpn l2tp remote-access outside-nexthop 192.168.255.1 + set vpn l2tp remote-access client-ip-pool start 192.168.255.2 + set vpn l2tp remote-access client-ip-pool stop 192.168.255.254 + set vpn l2tp remote-access authentication mode local + set vpn l2tp remote-access authentication local-users username test password test + set vpn l2tp remote-access authentication local-users username test rate-limit download 20480 + set vpn l2tp remote-access authentication local-users username test rate-limit upload 10240 + + vyos@vyos:~$ show vpn remote-access + ifname | username | calling-sid | ip | rate-limit | type | comp | state | uptime + -------+----------+--------------+---------------+-------------+------+------+--------+----------- + ppp0 | test | 192.168.0.36 | 192.168.255.2 | 20480/10240 | l2tp | | active | 00:06:30 + +RADIUS authentication +====================== + +To enable RADIUS based authentication, the authentication mode needs to be +changed withing the configuration. Previous settings like the local users, still +exists within the configuration, however they are not used if the mode has been +changed from local to radius. Once changed back to local, it will use all local +accounts again. + +.. code-block:: sh + + set vpn l2tp remote-access authentication mode <local|radius> + +Since the RADIUS server would be a single point of failure, multiple RADIUS +servers can be setup and will be used subsequentially. + +.. code-block:: sh + + set vpn l2tp remote-access authentication radius server 10.0.0.1 key 'foo' + set vpn l2tp remote-access authentication radius server 10.0.0.2 key 'foo' + +.. note:: Some RADIUS_ severs use an access control list which allows or denies + queries, make sure to add your VyOS router to the allowed client list. + +RADIUS source address +^^^^^^^^^^^^^^^^^^^^^ + +If you are using OSPF as IGP always the closets interface connected to the RADIUS +server is used. With VyOS 1.2 you can bind all outgoing RADIUS requests to a +single source IP e.g. the loopback interface. + +.. code-block:: sh + + set vpn l2tp remote-access authentication radius source-address 10.0.0.3 + +Above command will use `10.0.0.3` as source IPv4 address for all RADIUS queries +on this NAS. + +.. note:: The ``source-address`` must be configured on one of VyOS interface. + Best proctice would be a loopback or dummy interface. + +RADIUS bandwidth shaping attribute +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +To enable bandwidth shaping via RADIUS, the option rate-limit needs to be enabled. + +.. code-block:: sh + + set vpn l2tp remote-access authentication radius rate-limit enable + +The default RADIUS attribute for rate limiting is ``Filter-Id``, but you may also +redefine it. + +.. code-block:: sh + + set vpn l2tp remote-access authentication radius rate-limit attribute Download-Speed + +.. note:: If you set a custom RADIUS attribute you must define it on both + dictionaries at RADIUS server and client, which is the vyos router in our + example. + +The RADIUS dictionaries in VyOS are located at ``/usr/share/accel-ppp/radius/`` + +RADIUS advanced features +^^^^^^^^^^^^^^^^^^^^^^^^ + +Received RADIUS attributes have a higher priority than parameters defined within +the CLI configuration, refer to the explanation below. + +Allocation clients ip addresses by RADIUS +***************************************** + +If the RADIUS server sends the attribute ``Framed-IP-Address`` then this IP +address will be allocated to the client and the option ip-pool within the CLI +config is being ignored. + +Renaming clients interfaces by RADIUS +************************************* + +If the RADIUS server uses the attribute ``NAS-Port-Id``, ppp tunnels will be +renamed. + +.. note:: The value of the attribute ``NAS-Port-Id`` must be less than 16 + characters, otherwise the interface won't be renamed. + + +.. _`Google Public DNS`: https://developers.google.com/speed/public-dns +.. _Quad9: https://quad9.net +.. _CloudFlare: https://blog.cloudflare.com/announcing-1111 +.. _RADIUS: https://en.wikipedia.org/wiki/RADIUS +.. _FreeRADIUS: https://freeradius.org +.. _`Network Policy Server`: https://en.wikipedia.org/wiki/Network_Policy_Server +.. _accel-ppp: https://accel-ppp.org/ |