Revert "Recovery L2TP documentation for 1.2.1-1.2.2"

This reverts commit f02016d0adc7471ecf997d4bd9b4920e39d65aba.

1 files changed, 139 insertions, 37 deletions

diff --git a/docs/vpn/l2tp.rst b/docs/vpn/l2tp.rst
index 656da0ef..05496b46 100644
--- a/docs/vpn/l2tp.rst
+++ b/docs/vpn/l2tp.rst
@@ -1,10 +1,13 @@
 .. _l2tp:
 
-VyOS utilizes accel-ppp_ to provide L2TP server functionality. It can be used
+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):
@@ -15,25 +18,26 @@ with native Windows and Mac VPN clients):
   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 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 <username> password <password>
+  set vpn l2tp remote-access authentication local-users username test password 'test'
 
-In the example above an external IP of 203.0.113.2 is assumed.
+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 open:
+to allow the ports below:
 
 * 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:
+As well as the below to allow NAT-traversal:
 
 * UDP port 4500 (NAT-T)
 
@@ -42,7 +46,6 @@ 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'
@@ -55,8 +58,8 @@ Example:
   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.
+To allow VPN-clients access via your external address, a NAT rule is required:
+
 
 .. code-block:: sh
 
@@ -64,8 +67,9 @@ will need to add the appropriate source NAT rules to your configuration.
   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.
+
+VPN-clients will request configuration parameters, optionally you can DNS
+parameter to the client.
 
 .. code-block:: sh
 
@@ -76,56 +80,153 @@ needed as well.
    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.
+operational command, or **show l2tp-server sessions**
 
 .. 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
+   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.
 
-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.
+Bandwidth Shaping
+=================
 
-VyOS supports either `local` or `radius` user authentication:
+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>
 
-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:
+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 1.1.1.1 key 'foo'
-  set vpn l2tp remote-access authentication radius server 2.2.2.2 key 'foo'
+  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 make use of an access control list who is allowed
-   to query the server. Please configure your VyOS router in the allowed client
-   list.
+.. 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 e.g. OSPF as IGP always the nearest interface facing the RADIUS
+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 3.3.3.3
+  set vpn l2tp remote-access authentication radius source-address 10.0.0.3
 
-Above command will use `3.3.3.3` as source IPv4 address for all RADIUS queries
+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
@@ -133,3 +234,4 @@ on this NAS.
 .. _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/