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diff --git a/docs/vpn/l2tp_ipsec.rst b/docs/vpn/l2tp_ipsec.rst new file mode 100644 index 00000000..5d730ec0 --- /dev/null +++ b/docs/vpn/l2tp_ipsec.rst @@ -0,0 +1,124 @@ +.. _l2tp_ipsec: + +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 203.0.113.2 + set vpn l2tp remote-access client-ip-pool start 192.168.255.1 + 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 <username> password <password> + +In the example above an external IP of 203.0.113.2 is assumed. + +If a local firewall policy is in place on your external interface you will need +to open: + +* UDP port 500 (IKE) +* IP protocol number 50 (ESP) +* UDP port 1701 for IPsec + +In addition when NAT is detected by the VPN client ESP is encapsulated in UDP +for 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 destination port '50' + 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' + +Also note that if you wish to allow the VPN to be used for external access you +will need to add the appropriate source NAT rules to your configuration. + +.. 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 + +To be able to resolve when connected to the VPN, the following DNS rules are +needed as well. + +.. 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. + +.. code-block:: sh + + vyos@vyos:~$ show vpn remote-access + Active remote access VPN sessions: + User Proto Iface Tunnel IP TX byte RX byte Time + ---- ----- ----- --------- ------- ------- ---- + vyos L2TP l2tp0 192.168.255.1 3.2K 8.0K 00h06m13s + +RADIUS authentication +^^^^^^^^^^^^^^^^^^^^^ + +The above configuration made use of local accounts on the VyOS router for +authenticating L2TP/IPSec clients. In bigger environments usually something +like RADIUS_ (FreeRADIUS_ or Microsoft `Network Policy Server`_, NPS) is used. + +VyOS supports either `local` or `radius` user authentication: + +.. code-block:: sh + + set vpn l2tp remote-access authentication mode <local|radius> + +In addition one or more RADIUS_ servers can be configured to server for user +authentication. This is done using the `radius server` and `radius server key` +nodes: + +.. code-block:: sh + + set vpn l2tp remote-access authentication radius server 1.1.1.1 key 'foo' + set vpn l2tp remote-access authentication radius server 2.2.2.2 key 'foo' + +.. note:: Some RADIUS_ severs make use of an access control list who is allowed + to query the server. Please configure your VyOS router in the allowed client + list. + +RADIUS source address +********************* + +If you are using e.g. OSPF as IGP always the nearest interface facing 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 3.3.3.3 + +Above command will use `3.3.3.3` as source IPv4 address for all RADIUS queries +on this NAS. |