[Openvpn-devel] [PATCH v2 1/8] doc/man: Add an .rst formatted version of the man page

[David S. <da...@op...>]

This is the first step to move away from a manually editing g/nroff
encoded man page.

Some modifications was needed to ensure formatting was consistent and
rendered reasonably okay in GitHub and that the generated man page
(using rst2man) is looking as a proper man page.  Unsupported options
has also been moved into its own section.  HTML rendering directly
using rst2html has also been used to validate the conversion.

The rst2man and rst2html utilities comes from the python-docutils
project: https://docutils.sourceforge.io/

Signed-off-by: David Sommerseth <da...@op...>
---
 doc/openvpn.8.rst           | 5749 +++++++++++++++++++++++++++++++++++
 doc/unsupported-options.rst |   33 +
 2 files changed, 5782 insertions(+)
 create mode 100644 doc/openvpn.8.rst
 create mode 100644 doc/unsupported-options.rst

diff --git a/doc/openvpn.8.rst b/doc/openvpn.8.rst
new file mode 100644
index 00000000..713cd309
--- /dev/null
+++ b/doc/openvpn.8.rst
@@ -0,0 +1,5749 @@
+=========
+ openvpn
+=========
+-------------------------
+ Secure IP tunnel daemon
+-------------------------
+
+:Manual section: 8
+:Manual group: System Manager's Manual
+
+
+
+SYNOPSIS
+========
+| ``openvpn`` [ options ... ]
+| ``openvpn``  ``--help``
+
+
+
+INTRODUCTION
+============
+
+OpenVPN is an open source VPN daemon by James Yonan. Because OpenVPN
+tries to be a universal VPN tool offering a great deal of flexibility,
+there are a lot of options on this manual page. If you're new to
+OpenVPN, you might want to skip ahead to the examples section where you
+will see how to construct simple VPNs on the command line without even
+needing a configuration file.
+
+Also note that there's more documentation and examples on the OpenVPN
+web site: https://openvpn.net/
+
+And if you would like to see a shorter version of this manual, see the
+openvpn usage message which can be obtained by running **openvpn**
+without any parameters.
+
+
+
+DESCRIPTION
+===========
+
+OpenVPN is a robust and highly flexible VPN daemon. OpenVPN supports
+SSL/TLS security, ethernet bridging, TCP or UDP tunnel transport through
+proxies or NAT, support for dynamic IP addresses and DHCP, scalability
+to hundreds or thousands of users, and portability to most major OS
+platforms.
+
+OpenVPN is tightly bound to the OpenSSL library, and derives much of its
+crypto capabilities from it.
+
+OpenVPN supports conventional encryption using a pre-shared secret key
+**(Static Key mode)** or public key security **(SSL/TLS mode)** using
+client & server certificates. OpenVPN also supports non-encrypted
+TCP/UDP tunnels.
+
+OpenVPN is designed to work with the **TUN/TAP** virtual networking
+interface that exists on most platforms.
+
+Overall, OpenVPN aims to offer many of the key features of IPSec but
+with a relatively lightweight footprint.
+
+
+
+OPTIONS
+=======
+
+OpenVPN allows any option to be placed either on the command line or in
+a configuration file. Though all command line options are preceded by a
+double-leading-dash ("--"), this prefix can be removed when an option is
+placed in a configuration file.
+
+--help
+
+  Show options.
+
+--config file
+  Load additional config options from ``file`` where each line corresponds
+  to one command line option, but with the leading '--' removed.
+
+  If ``--config file`` is the only option to the openvpn command, the
+  ``--config`` can be removed, and the command can be given as ``openvpn
+  file``
+
+  Note that configuration files can be nested to a reasonable depth.
+
+  Double quotation or single quotation characters ("", '') can be used to
+  enclose single parameters containing whitespace, and "#" or ";"
+  characters in the first column can be used to denote comments.
+
+  Note that OpenVPN 2.0 and higher performs backslash-based shell escaping
+  for characters not in single quotations, so the following mappings
+  should be observed:
+  ::
+
+      \\       Maps to a single backslash character (\).
+      \"       Pass a literal doublequote character ("), don't
+               interpret it as enclosing a parameter.
+      \[SPACE] Pass a literal space or tab character, don't
+               interpret it as a parameter delimiter.
+
+  For example on Windows, use double backslashes to represent pathnames:
+  ::
+
+      secret "c:\\OpenVPN\\secret.key"
+
+
+  For examples of configuration files, see
+  https://openvpn.net/community-resources/how-to/
+
+  Here is an example configuration file:
+  ::
+
+      #
+      # Sample OpenVPN configuration file for
+      # using a pre-shared static key.
+      #
+      # '#' or ';' may be used to delimit comments.
+
+      # Use a dynamic tun device.
+      dev tun
+
+      # Our remote peer
+      remote mypeer.mydomain
+
+      # 10.1.0.1 is our local VPN endpoint
+      # 10.1.0.2 is our remote VPN endpoint
+      ifconfig 10.1.0.1 10.1.0.2
+
+      # Our pre-shared static key
+      secret static.key
+
+
+Tunnel Options:
+---------------
+
+--mode m
+  Set OpenVPN major mode. By default, OpenVPN runs in point-to-point mode
+  (:code:`p2p`). OpenVPN 2.0 introduces a new mode (:code:`server`) which
+  implements a multi-client server capability.
+
+--local host
+  Local host name or IP address for bind. If specified, OpenVPN will bind
+  to this address only. If unspecified, OpenVPN will bind to all
+  interfaces.
+
+--remote args
+  Remote host name or IP address.  It supports two additional optional
+  arguments: ``port`` and ``proto``.  On the client, multiple ``--remote``
+  options may be specified for redundancy, each referring to a different
+  OpenVPN server. Specifying multiple ``--remote`` options for this
+  purpose is a special case of the more general connection-profile
+  feature. See the ``<connection>`` documentation below.
+
+  The OpenVPN client will try to connect to a server at ``host:port`` in
+  the order specified by the list of ``--remote`` options.
+
+  Examples:
+  ::
+
+     remote server.example.net
+     remote server.example.net 1194
+     remote server.example.net tcp
+
+  ``proto`` indicates the protocol to use when connecting with the remote,
+  and may be :code:`tcp` or :code:`udp`.
+
+  For forcing IPv4 or IPv6 connection suffix tcp or udp with 4/6 like
+  udp4/udp6/tcp4/tcp6.
+
+  The client will move on to the next host in the list, in the event of
+  connection failure. Note that at any given time, the OpenVPN client will
+  at most be connected to one server.
+
+  Note that since UDP is connectionless, connection failure is defined by
+  the ``--ping`` and ``--ping-restart`` options.
+
+  Note the following corner case: If you use multiple ``--remote``
+  options, AND you are dropping root privileges on the client with
+  ``--user`` and/or ``--group`` AND the client is running a non-Windows
+  OS, if the client needs to switch to a different server, and that server
+  pushes back different TUN/TAP or route settings, the client may lack the
+  necessary privileges to close and reopen the TUN/TAP interface. This
+  could cause the client to exit with a fatal error.
+
+  If ``--remote`` is unspecified, OpenVPN will listen for packets from any
+  IP address, but will not act on those packets unless they pass all
+  authentication tests. This requirement for authentication is binding on
+  all potential peers, even those from known and supposedly trusted IP
+  addresses (it is very easy to forge a source IP address on a UDP
+  packet).
+
+  When used in TCP mode, ``--remote`` will act as a filter, rejecting
+  connections from any host which does not match ``host``.
+
+  If ``host`` is a DNS name which resolves to multiple IP addresses,
+  OpenVPN will try them in the order that the system getaddrinfo()
+  presents them, so priorization and DNS randomization is done by the
+  system library. Unless an IP version is forced by the protocol
+  specification (4/6 suffix), OpenVPN will try both IPv4 and IPv6
+  addresses, in the order getaddrinfo() returns them.
+
+--remote-random-hostname
+  Prepend a random string (6 bytes, 12 hex characters) to hostname to
+  prevent DNS caching. For example, "foo.bar.gov" would be modified to
+  "<random-chars>.foo.bar.gov".
+
+--proto-force p
+  When iterating through connection profiles, only consider profiles using
+  protocol ``p`` (:code:`tcp` \| :code:`udp`).
+
+--remote-random
+  When multiple ``--remote`` address/ports are specified, or if connection
+  profiles are being used, initially randomize the order of the list as a
+  kind of basic load-balancing measure.
+
+--proto p
+  Use protocol ``p`` for communicating with remote host. ``p`` can be
+  :code:`udp`, :code:`tcp-client`, or :code:`tcp-server`.
+
+  The default protocol is :code:`udp` when ``--proto`` is not specified.
+
+  For UDP operation, ``--proto udp`` should be specified on both peers.
+
+  For TCP operation, one peer must use ``--proto tcp-server`` and the
+  other must use ``--proto tcp-client``. A peer started with
+  :code:`tcp-server` will wait indefinitely for an incoming connection. A peer
+  started with :code:`tcp-client` will attempt to connect, and if that fails,
+  will sleep for 5 seconds (adjustable via the ``--connect-retry`` option)
+  and try again infinite or up to N retries (adjustable via the
+  ``--connect-retry-max`` option). Both TCP client and server will
+  simulate a SIGUSR1 restart signal if either side resets the connection.
+
+  OpenVPN is designed to operate optimally over UDP, but TCP capability is
+  provided for situations where UDP cannot be used. In comparison with
+  UDP, TCP will usually be somewhat less efficient and less robust when
+  used over unreliable or congested networks.
+
+  This article outlines some of problems with tunneling IP over TCP:
+  http://sites.inka.de/sites/bigred/devel/tcp-tcp.html
+
+  There are certain cases, however, where using TCP may be advantageous
+  from a security and robustness perspective, such as tunneling non-IP or
+  application-level UDP protocols, or tunneling protocols which don't
+  possess a built-in reliability layer.
+
+--connect-retry args
+  Wait ``n`` seconds between connection attempts (default :code:`5`).
+  Repeated reconnection attempts are slowed down after 5 retries per
+  remote by doubling the wait time after each unsuccessful attempt. An
+  optional argument ``max`` specifies the maximum value of wait time in
+  seconds at which it gets capped (default :code:`300`).
+
+--connect-retry-max n
+  ``n`` specifies the number of times each ``--remote`` or
+  ``<connection>`` entry is tried. Specifying ``n`` as one would try each
+  entry exactly once. A successful connection resets the counter.
+  (default *unlimited*).
+
+--show-proxy-settings
+  Show sensed HTTP or SOCKS proxy settings. Currently, only Windows
+  clients support this option.
+
+--http-proxy args
+  Connect to remote host through an HTTP proxy.  This requires at least an
+  address ``server`` and ``port`` argument.  If HTTP Proxy-Authenticate
+  is required, a file name to an ``authfile`` file containing a username
+  and password on 2 lines can be given, or :code:`stdin` to prompt from
+  console. Its content can also be specified in the config file with the
+  ``--http-proxy-user-pass`` option. (See section on inline files)
+
+  The last optional argument is an ``auth-method`` which should be one
+  of :code:`none`, :code:`basic`, or :code:`ntlm`.
+
+  HTTP Digest authentication is supported as well, but only via the
+  :code:`auto` or :code:`auto-nct` flags (below).  This must replace
+  the ``authfile`` argument.
+
+  The :code:`auto` flag causes OpenVPN to automatically determine the
+  ``auth-method`` and query stdin or the management interface for
+  username/password credentials, if required. This flag exists on OpenVPN
+  2.1 or higher.
+
+  The ``auto-nct`` flag (no clear-text auth) instructs OpenVPN to
+  automatically determine the authentication method, but to reject weak
+  authentication protocols such as HTTP Basic Authentication.
+
+  Examples:
+  ::
+
+     http-proxy proxy.example.net 3128
+     http-proxy proxy.example.net 3128 authfile.txt
+     http-proxy proxy.example.net 3128 stdin
+     http-proxy proxy.example.net 3128 auto basic
+     http-proxy proxy.example.net 3128 auto-nct ntlm
+
+--http-proxy-option args
+  Set extended HTTP proxy options. Requires an option ``type`` as argument
+  and an optional ``parameter`` to the type.  Repeat to set multiple
+  options.
+
+  :code:`VERSION` ``version``
+      Set HTTP version number to ``version`` (default :code:`1.0`).
+
+  :code:`AGENT` ``user-agent``
+      Set HTTP "User-Agent" string to ``user-agent``.
+
+  :code:`CUSTOM-HEADER` ``name`` ``content``
+      Adds the custom Header with ``name`` as name and ``content`` as
+      the content of the custom HTTP header.
+
+  Examples:
+  ::
+
+     http-proxy-option VERSION 1.1
+     http-proxy-option AGENT OpenVPN/2.4
+     http-proxy-option X-Proxy-Flag some-flags
+
+--socks-proxy args
+  Connect to remote host through a Socks5 proxy.  A required ``server``
+  argument is needed.  Optionally a ``port`` (default :code:`1080`) and
+  ``authfile`` can be given.  The ``authfile`` is a file containing a
+  username and password on 2 lines, or :code:`stdin` can be used to
+  prompt from console.
+
+--resolv-retry n
+  If hostname resolve fails for ``--remote``, retry resolve for ``n``
+  seconds before failing.
+
+  Set ``n`` to "infinite" to retry indefinitely.
+
+  By default, ``--resolv-retry infinite`` is enabled. You can disable by
+  setting n=0.
+
+--float
+  Allow remote peer to change its IP address and/or port number, such as
+  due to DHCP (this is the default if ``--remote`` is not used).
+  ``--float`` when specified with ``--remote`` allows an OpenVPN session
+  to initially connect to a peer at a known address, however if packets
+  arrive from a new address and pass all authentication tests, the new
+  address will take control of the session. This is useful when you are
+  connecting to a peer which holds a dynamic address such as a dial-in
+  user or DHCP client.
+
+  Essentially, ``--float`` tells OpenVPN to accept authenticated packets
+  from any address, not only the address which was specified in the
+  ``--remote`` option.
+
+--ipchange cmd
+  Run command ``cmd`` when our remote ip-address is initially
+  authenticated or changes.
+
+  ``cmd`` consists of a path to script (or executable program), optionally
+  followed by arguments. The path and arguments may be single- or
+  double-quoted and/or escaped using a backslash, and should be separated
+  by one or more spaces.
+
+  When ``cmd`` is executed two arguments are appended after any arguments
+  specified in ``cmd`` , as follows:
+  ::
+
+     cmd ip address port number
+
+  Don't use ``--ipchange`` in ``--mode server`` mode. Use a
+  ``--client-connect`` script instead.
+
+  See the `Environmental Variables`_ section below for additional
+  parameters passed as environmental variables.
+
+  If you are running in a dynamic IP address environment where the IP
+  addresses of either peer could change without notice, you can use this
+  script, for example, to edit the :code:`/etc/hosts` file with the current
+  address of the peer. The script will be run every time the remote peer
+  changes its IP address.
+
+  Similarly if *our* IP address changes due to DHCP, we should configure
+  our IP address change script (see man page for ``dhcpcd``\(8)) to
+  deliver a ``SIGHUP`` or ``SIGUSR1`` signal to OpenVPN. OpenVPN will
+  then reestablish a connection with its most recently authenticated
+  peer on its new IP address.
+
+--port port
+  TCP/UDP port number or port name for both local and remote (sets both
+  ``--lport`` and ``--rport`` options to given port). The current default
+  of 1194 represents the official IANA port number assignment for OpenVPN
+  and has been used since version 2.0-beta17. Previous versions used port
+  5000 as the default.
+
+--lport port
+  Set local TCP/UDP port number or name. Cannot be used together with
+  ``--nobind`` option.
+
+--rport port
+  Set TCP/UDP port number or name used by the ``--remote`` option. The
+  port can also be set directly using the ``--remote`` option.
+
+--bind keywords
+  Bind to local address and port. This is the default unless any of
+  ``--proto tcp-client`` , ``--http-proxy`` or ``--socks-proxy`` are used.
+
+  If the optional :code:`ipv6only` keyword is present OpenVPN will bind only
+  to IPv6 (as opposed to IPv6 and IPv4) when a IPv6 socket is opened.
+
+--nobind
+  Do not bind to local address and port. The IP stack will allocate a
+  dynamic port for returning packets. Since the value of the dynamic port
+  could not be known in advance by a peer, this option is only suitable
+  for peers which will be initiating connections by using the --remote
+  option.
+
+--dev device
+  TUN/TAP virtual network device which can be :code:`tunX`, :code:`tapX`,
+  :code:`null` or an arbitrary name string (:code:`X` can be omitted for
+  a dynamic device.)
+
+  See examples section below for an example on setting up a TUN device.
+
+  You must use either tun devices on both ends of the connection or tap
+  devices on both ends. You cannot mix them, as they represent different
+  underlying network layers:
+
+  :code:`tun`
+      devices encapsulate IPv4 or IPv6 (OSI Layer 3)
+
+  :code:`tap`
+      devices encapsulate Ethernet 802.3 (OSI Layer 2).
+
+--dev-type device-type
+  Which device type are we using? ``device-type`` should be :code:`tun`
+  (OSI Layer 3) or :code:`tap` (OSI Layer 2). Use this option only if
+  the TUN/TAP device used with ``--dev`` does not begin with :code:`tun`
+  or :code:`tap`.
+
+--topology mode
+  Configure virtual addressing topology when running in ``--dev tun``
+  mode. This directive has no meaning in ``--dev tap`` mode, which always
+  uses a :code:`subnet` topology.
+
+  If you set this directive on the server, the ``--server`` and
+  ``--server-bridge`` directives will automatically push your chosen
+  topology setting to clients as well. This directive can also be manually
+  pushed to clients. Like the ``--dev`` directive, this directive must
+  always be compatible between client and server.
+
+  ``mode`` can be one of:
+
+  :code:`net30`
+    Use a point-to-point topology, by allocating one /30 subnet
+    per client. This is designed to allow point-to-point semantics when some
+    or all of the connecting clients might be Windows systems. This is the
+    default on OpenVPN 2.0.
+
+  :code:`p2p`
+    Use a point-to-point topology where the remote endpoint of
+    the client's tun interface always points to the local endpoint of the
+    server's tun interface. This mode allocates a single IP address per
+    connecting client. Only use when none of the connecting clients are
+    Windows systems.
+
+  :code:`subnet`
+    Use a subnet rather than a point-to-point topology by
+    configuring the tun interface with a local IP address and subnet mask,
+    similar to the topology used in ``--dev tap`` and ethernet bridging
+    mode. This mode allocates a single IP address per connecting client and
+    works on Windows as well. Only available when server and clients are
+    OpenVPN 2.1 or higher, or OpenVPN 2.0.x which has been manually patched
+    with the ``--topology`` directive code. When used on Windows, requires
+    version 8.2 or higher of the TAP-Win32 driver. When used on \*nix,
+    requires that the tun driver supports an
+    ```ifconfig </man/man2html?8+ifconfig>`__``\ (8) command which sets a
+    subnet instead of a remote endpoint IP address.
+
+  This option exists in OpenVPN 2.1 or higher.
+
+  *Note:* Using ``--topology subnet`` changes the interpretation of the
+  arguments of ``--ifconfig`` to mean "address netmask", no longer "local
+  remote".
+
+--dev-node node
+  Explicitly set the device node rather than using :code:`/dev/net/tun`,
+  :code:`/dev/tun`, :code:`/dev/tap`, etc. If OpenVPN cannot figure out
+  whether ``node`` is a TUN or TAP device based on the name, you should
+  also specify ``--dev-type tun`` or ``--dev-type tap``.
+
+  Under Mac OS X this option can be used to specify the default tun
+  implementation. Using ``--dev-node utun`` forces usage of the native
+  Darwin tun kernel support. Use ``--dev-node utunN`` to select a specific
+  utun instance. To force using the :code:`tun.kext` (:code:`/dev/tunX`)
+  use ``--dev-node tun``. When not specifying a ``--dev-node`` option
+  openvpn will first try to open utun, and fall back to tun.kext.
+
+  On Windows systems, select the TAP-Win32 adapter which is named ``node``
+  in the Network Connections Control Panel or the raw GUID of the adapter
+  enclosed by braces. The ``--show-adapters`` option under Windows can
+  also be used to enumerate all available TAP-Win32 adapters and will show
+  both the network connections control panel name and the GUID for each
+  TAP-Win32 adapter.
+
+--lladdr address
+  Specify the link layer address, more commonly known as the MAC address.
+  Only applied to TAP devices.
+
+--iproute cmd
+  Set alternate command to execute instead of default ``iproute2`` command.
+  May be used in order to execute OpenVPN in unprivileged environment.
+
+--ifconfig args
+  Set TUN/TAP adapter parameters. It requires the *IP address* of the local
+  VPN endpoint. For TUN devices in point-to-point mode, the next argument
+  must be the VPN IP address of the remote VPN endpoint. For TAP devices,
+  or TUN devices used with ``--topology subnet``, the second argument
+  is the subnet mask of the virtual network segment which is being created
+  or connected to.
+
+  For TUN devices, which facilitate virtual point-to-point IP connections
+  (when used in ``--topology net30`` or ``p2p`` mode), the proper usage of
+  ``--ifconfig`` is to use two private IP addresses which are not a member
+  of any existing subnet which is in use. The IP addresses may be
+  consecutive and should have their order reversed on the remote peer.
+  After the VPN is established, by pinging ``rn``, you will be pinging
+  across the VPN.
+
+  For TAP devices, which provide the ability to create virtual ethernet
+  segments, or TUN devices in ``--topology subnet`` mode (which create
+  virtual "multipoint networks"), ``--ifconfig`` is used to set an IP
+  address and subnet mask just as a physical ethernet adapter would be
+  similarly configured. If you are attempting to connect to a remote
+  ethernet bridge, the IP address and subnet should be set to values which
+  would be valid on the the bridged ethernet segment (note also that DHCP
+  can be used for the same purpose).
+
+  This option, while primarily a proxy for the ``ifconfig``\(8) command,
+  is designed to simplify TUN/TAP tunnel configuration by providing a
+  standard interface to the different ifconfig implementations on
+  different platforms.
+
+  ``--ifconfig`` parameters which are IP addresses can also be specified
+  as a DNS or /etc/hosts file resolvable name.
+
+  For TAP devices, ``--ifconfig`` should not be used if the TAP interface
+  will be getting an IP address lease from a DHCP server.
+
+  Examples:
+  ::
+
+     # tun device in net30/p2p mode
+     ifconfig 10.8.0.2 10.8.0.1
+
+     # tun/tap device in subnet mode
+     ifconfig 10.8.0.2 255.255.255.0
+
+--ifconfig-noexec
+  Don't actually execute ifconfig/netsh commands, instead pass
+  ``--ifconfig`` parameters to scripts using environmental variables.
+
+--ifconfig-nowarn
+  Don't output an options consistency check warning if the ``--ifconfig``
+  option on this side of the connection doesn't match the remote side.
+  This is useful when you want to retain the overall benefits of the
+  options consistency check (also see ``--disable-occ`` option) while only
+  disabling the ifconfig component of the check.
+
+  For example, if you have a configuration where the local host uses
+  ``--ifconfig`` but the remote host does not, use ``--ifconfig-nowarn``
+  on the local host.
+
+  This option will also silence warnings about potential address conflicts
+  which occasionally annoy more experienced users by triggering "false
+  positive" warnings.
+
+--route args
+  Add route to routing table after connection is established. Multiple
+  routes can be specified. Routes will be automatically torn down in
+  reverse order prior to TUN/TAP device close.
+
+  Valid syntaxes:
+  ::
+
+      route network/IP
+      route network/IP netmask
+      route network/IP netmask gateway
+      route network/IP netmask gateway metric
+
+  This option is intended as a convenience proxy for the ``route``\(8)
+  shell command, while at the same time providing portable semantics
+  across OpenVPN's platform space.
+
+  ``netmask``
+        defaults to :code:`255.255.255.255` when not given
+
+  ``gateway``
+        default taken from ``--route-gateway`` or the second
+        parameter to ``--ifconfig`` when ``--dev tun`` is specified.
+
+  ``metric``
+        default taken from ``--route-metric`` if set, otherwise :code:`0`.
+
+  The default can be specified by leaving an option blank or setting it to
+  :code:`default`.
+
+  The ``network`` and ``gateway`` parameters can also be specified as a
+  DNS or :code:`/etc/hosts` file resolvable name, or as one of three special
+  keywords:
+
+  :code:`vpn_gateway`
+      The remote VPN endpoint address (derived either from
+      ``--route-gateway`` or the second parameter to ``--ifconfig``
+      when ``--dev tun`` is specified).
+
+  :code:`net_gateway`
+      The pre-existing IP default gateway, read from the
+      routing table (not supported on all OSes).
+
+  :code:`remote_host`
+      The ``--remote`` address if OpenVPN is being run in
+      client mode, and is undefined in server mode.
+
+--route-gateway arg
+  Specify a default *gateway* for use with ``--route``.
+
+  If :code:`dhcp` is specified as the parameter, the gateway address will
+  be extracted from a DHCP negotiation with the OpenVPN server-side LAN.
+
+  Valid syntaxes:
+  ::
+
+      route-gateway gateway
+      route-gateway dhcp
+
+
+--route-metric m
+  Specify a default metric ``m`` for use with ``--route``.
+
+--route-delay args
+  Valid syntaxes:
+  ::
+
+       route-delay
+       route-delay n
+       route-delay n m
+
+  Delay ``n`` seconds (default :code:`0`) after connection establishment,
+  before adding routes. If ``n`` is :code:`0`, routes will be added
+  immediately upon connection establishment. If ``--route-delay`` is
+  omitted, routes will be added immediately after TUN/TAP device open and
+  ``--up`` script execution, before any ``--user`` or ``--group`` privilege
+  downgrade (or ``--chroot`` execution.)
+
+  This option is designed to be useful in scenarios where DHCP is used to
+  set tap adapter addresses. The delay will give the DHCP handshake time
+  to complete before routes are added.
+
+  On Windows, ``--route-delay`` tries to be more intelligent by waiting
+  ``w`` seconds (default :code:`30` by default) for the TAP-Win32 adapter
+  to come up before adding routes.
+
+--route-up cmd
+  Run command ``cmd`` after routes are added, subject to ``--route-delay``.
+
+  ``cmd`` consists of a path to script (or executable program), optionally
+  followed by arguments. The path and arguments may be single- or
+  double-quoted and/or escaped using a backslash, and should be separated
+  by one or more spaces.
+
+  See the `Environmental Variables`_ section below for additional
+  parameters passed as environmental variables.
+
+--route-pre-down cmd
+  Run command ``cmd`` before routes are removed upon disconnection.
+
+  ``cmd`` consists of a path to script (or executable program), optionally
+  followed by arguments. The path and arguments may be single- or
+  double-quoted and/or escaped using a backslash, and should be separated
+  by one or more spaces.
+
+  See the `Environmental Variables`_ section below for additional
+  parameters passed as environmental variables.
+
+--route-noexec
+  Don't add or remove routes automatically. Instead pass routes to
+  ``--route-up`` script using environmental variables.
+
+--route-nopull
+  When used with ``--client`` or ``--pull``, accept options pushed by
+  server EXCEPT for routes, block-outside-dns and dhcp options like DNS
+  servers.
+
+  When used on the client, this option effectively bars the server from
+  adding routes to the client's routing table, however note that this
+  option still allows the server to set the TCP/IP properties of the
+  client's TUN/TAP interface.
+
+--allow-pull-fqdn
+  Allow client to pull DNS names from server (rather than being limited to
+  IP address) for ``--ifconfig``, ``--route``, and ``--route-gateway``.
+
+--client-nat args
+  This pushable client option sets up a stateless one-to-one NAT rule on
+  packet addresses (not ports), and is useful in cases where routes or
+  ifconfig settings pushed to the client would create an IP numbering
+  conflict.
+
+  Examples:
+  ::
+
+      client-nat snat 192.168.0.0/255.255.0.0
+      client-nat dnat 10.64.0.0/255.255.0.0
+
+  ``network/netmask`` (for example :code:`192.168.0.0/255.255.0.0`) defines
+  the local view of a resource from the client perspective, while
+  ``alias/netmask`` (for example :code:`10.64.0.0/255.255.0.0`) defines the
+  remote view from the server perspective.
+
+  Use :code:`snat` (source NAT) for resources owned by the client and
+  :code:`dnat` (destination NAT) for remote resources.
+
+  Set ``--verb 6`` for debugging info showing the transformation of
+  src/dest addresses in packets.
+
+--redirect-gateway flags
+  Automatically execute routing commands to cause all outgoing IP traffic
+  to be redirected over the VPN. This is a client-side option.
+
+  This option performs three steps:
+
+  (1)  Create a static route for the ``--remote`` address which
+       forwards to the pre-existing default gateway. This is done so that
+       ``(3)`` will not create a routing loop.
+
+  (2)  Delete the default gateway route.
+
+  (3)  Set the new default gateway to be the VPN endpoint address
+       (derived either from ``--route-gateway`` or the second parameter to
+       ``--ifconfig`` when ``--dev tun`` is specified).
+
+  When the tunnel is torn down, all of the above steps are reversed so
+  that the original default route is restored.
+
+  Option flags:
+
+  :code:`local`
+      Add the :code:`local` flag if both OpenVPN peers are directly
+      connected via a common subnet, such as with wireless. The
+      :code:`local` flag will cause step ``(1)`` above to be omitted.
+
+  :code:`autolocal`
+      Try to automatically determine whether to enable :code:`local`
+      flag above.
+
+  :code:`def1`
+      Use this flag to override the default gateway by using
+      :code:`0.0.0.0/1` and :code:`128.0.0.0/1` rather than
+      :code:`0.0.0.0/0`. This has the benefit of overriding but not
+      wiping out the original default gateway.
+
+  :code:`bypass-dhcp`
+      Add a direct route to the DHCP server (if it is non-local) which
+      bypasses the tunnel (Available on Windows clients, may not be
+      available on non-Windows clients).
+
+  :code:`bypass-dns`
+      Add a direct route to the DNS server(s) (if they are non-local)
+      which bypasses the tunnel (Available on Windows clients, may
+      not be available on non-Windows clients).
+
+  :code:`block-local`
+      Block access to local LAN when the tunnel is active, except for
+      the LAN gateway itself. This is accomplished by routing the local
+      LAN (except for the LAN gateway address) into the tunnel.
+
+  :code:`ipv6`
+      Redirect IPv6 routing into the tunnel. This works similar to
+      the :code:`def1` flag, that is, more specific IPv6 routes are added
+      (:code:`2000::/4`, :code:`3000::/4`), covering the whole IPv6
+      unicast space.
+
+  :code:`!ipv4`
+      Do not redirect IPv4 traffic - typically used in the flag pair
+      :code:`ipv6 !ipv4` to redirect IPv6-only.
+
+--link-mtu n
+  Sets an upper bound on the size of UDP packets which are sent between
+  OpenVPN peers. *It's best not to set this parameter unless you know what
+  you're doing.*
+
+--redirect-private flags
+  Like ``--redirect-gateway``, but omit actually changing the default gateway.
+  Useful when pushing private subnets.
+
+--block-ipv6
+  On the client, instead of sending IPv6 packets over the VPN tunnel, all
+  IPv6 packets are answered with an ICMPv6 no route host message. On the
+  server, all IPv6 packets from clients are answered with an ICMPv6 no
+  route to host message. This options is intended for cases when IPv6
+  should be blocked and other options are not available. ``--block-ipv6``
+  will use the remote IPv6 as source address of the ICMPv6 packets if set,
+  otherwise will use :code:`fe80::7` as source address.
+
+  For this option to make sense you actually have to route traffic to the
+  tun interface. The following example config block would send all IPv6
+  traffic to OpenVPN and answer all requests with no route to host,
+  effectively blocking IPv6.
+
+  **Client config**
+    ::
+
+       --ifconfig-ipv6 fd15:53b6:dead::2/64 fd15:53b6:dead::1
+       --redirect-gateway ipv6
+       --block-ipv6
+
+  **Server config**
+    Push a "valid" ipv6 config to the client and block on the server
+    ::
+
+       --push "ifconfig-ipv6 fd15:53b6:dead::2/64 fd15:53b6:dead::1"
+       --push "redirect-gateway ipv6"
+       --block-ipv6
+
+--tun-mtu n
+  Take the TUN device MTU to be **n** and derive the link MTU from it
+  (default :code:`1500`). In most cases, you will probably want to leave
+  this parameter set to its default value.
+
+  The MTU (Maximum Transmission Units) is the maximum datagram size in
+  bytes that can be sent unfragmented over a particular network path.
+  OpenVPN requires that packets on the control or data channels be sent
+  unfragmented.
+
+  MTU problems often manifest themselves as connections which hang during
+  periods of active usage.
+
+  It's best to use the ``--fragment`` and/or ``--mssfix`` options to deal
+  with MTU sizing issues.
+
+--tun-mtu-extra n
+  Assume that the TUN/TAP device might return as many as ``n`` bytes more
+  than the ``--tun-mtu`` size on read. This parameter defaults to 0, which
+  is sufficient for most TUN devices. TAP devices may introduce additional
+  overhead in excess of the MTU size, and a setting of 32 is the default
+  when TAP devices are used. This parameter only controls internal OpenVPN
+  buffer sizing, so there is no transmission overhead associated with
+  using a larger value.
+
+--mtu-disc type
+  Should we do Path MTU discovery on TCP/UDP channel? Only supported on
+  OSes such as Linux that supports the necessary system call to set.
+
+  Valid types:
+
+  :code:`no`      Never send DF (Don't Fragment) frames
+
+  :code:`maybe`   Use per-route hints
+
+  :code:`yes`     Always DF (Don't Fragment)
+
+--mtu-test
+  To empirically measure MTU on connection startup, add the ``--mtu-test``
+  option to your configuration. OpenVPN will send ping packets of various
+  sizes to the remote peer and measure the largest packets which were
+  successfully received. The ``--mtu-test`` process normally takes about 3
+  minutes to complete.
+
+--fragment max
+  Enable internal datagram fragmentation so that no UDP datagrams are sent
+  which are larger than ``max`` bytes.
+
+  The ``max`` parameter is interpreted in the same way as the
+  ``--link-mtu`` parameter, i.e. the UDP packet size after encapsulation
+  overhead has been added in, but not including the UDP header itself.
+
+  The ``--fragment`` option only makes sense when you are using the UDP
+  protocol (``--proto udp``).
+
+  ``--fragment`` adds 4 bytes of overhead per datagram.
+
+  See the ``--mssfix`` option below for an important related option to
+  ``--fragment``.
+
+  It should also be noted that this option is not meant to replace UDP
+  fragmentation at the IP stack level. It is only meant as a last resort
+  when path MTU discovery is broken. Using this option is less efficient
+  than fixing path MTU discovery for your IP link and using native IP
+  fragmentation instead.
+
+  Having said that, there are circumstances where using OpenVPN's internal
+  fragmentation capability may be your only option, such as tunneling a
+  UDP multicast stream which requires fragmentation.
+
+--mssfix max
+  Announce to TCP sessions running over the tunnel that they should limit
+  their send packet sizes such that after OpenVPN has encapsulated them,
+  the resulting UDP packet size that OpenVPN sends to its peer will not
+  exceed ``max`` bytes. The default value is :code:`1450`.
+
+  The ``max`` parameter is interpreted in the same way as the
+  ``--link-mtu`` parameter, i.e. the UDP packet size after encapsulation
+  overhead has been added in, but not including the UDP header itself.
+  Resulting packet would be at most 28 bytes larger for IPv4 and 48 bytes
+  for IPv6 (20/40 bytes for IP header and 8 bytes for UDP header). Default
+  value of 1450 allows IPv4 packets to be transmitted over a link with MTU
+  1473 or higher without IP level fragmentation.
+
+  The ``--mssfix`` option only makes sense when you are using the UDP
+  protocol for OpenVPN peer-to-peer communication, i.e. ``--proto udp``.
+
+  ``--mssfix`` and ``--fragment`` can be ideally used together, where
+  ``--mssfix`` will try to keep TCP from needing packet fragmentation in
+  the first place, and if big packets come through anyhow (from protocols
+  other than TCP), ``--fragment`` will internally fragment them.
+
+  Both ``--fragment`` and ``--mssfix`` are designed to work around cases
+  where Path MTU discovery is broken on the network path between OpenVPN
+  peers.
+
+  The usual symptom of such a breakdown is an OpenVPN connection which
+  successfully starts, but then stalls during active usage.
+
+  If ``--fragment`` and ``--mssfix`` are used together, ``--mssfix`` will
+  take its default ``max`` parameter from the ``--fragment max`` option.
+
+  Therefore, one could lower the maximum UDP packet size to 1300 (a good
+  first try for solving MTU-related connection problems) with the
+  following options:
+  ::
+
+     --tun-mtu 1500 --fragment 1300 --mssfix
+
+--sndbuf size
+  Set the TCP/UDP socket send buffer size. Defaults to operation system
+  default.
+
+--rcvbuf size
+  Set the TCP/UDP socket receive buffer size. Defaults to operation system
+  default.
+
+--mark value
+  Mark encrypted packets being sent with value. The mark value can be
+  matched in policy routing and packetfilter rules. This option is only
+  supported in Linux and does nothing on other operating systems.
+
+--socket-flags flags
+  Apply the given flags to the OpenVPN transport socket. Currently, only
+  :code:`TCP_NODELAY` is supported.
+
+  The :code:`TCP_NODELAY` socket flag is useful in TCP mode, and causes the
+  kernel to send tunnel packets immediately over the TCP connection without
+  trying to group several smaller packets into a larger packet.  This can
+  result in a considerably improvement in latency.
+
+  This option is pushable from server to client, and should be used on
+  both client and server for maximum effect.
+
+--txqueuelen n
+  *(Linux only)* Set the TX queue length on the TUN/TAP interface.
+  Currently defaults to 100.
+
+--shaper n
+  Limit bandwidth of outgoing tunnel data to ``n`` bytes per second on the
+  TCP/UDP port. Note that this will only work if mode is set to
+  :code:`p2p`.  If you want to limit the bandwidth in both directions, use
+  this option on both peers.
+
+  OpenVPN uses the following algorithm to implement traffic shaping: Given
+  a shaper rate of ``n`` bytes per second, after a datagram write of ``b``
+  bytes is queued on the TCP/UDP port, wait a minimum of ``(b / n)``
+  seconds before queuing the next write.
+
+  It should be noted that OpenVPN supports multiple tunnels between the
+  same two peers, allowing you to construct full-speed and reduced
+  bandwidth tunnels at the same time, routing low-priority data such as
+  off-site backups over the reduced bandwidth tunnel, and other data over
+  the full-speed tunnel.
+
+  Also note that for low bandwidth tunnels (under 1000 bytes per second),
+  you should probably use lower MTU values as well (see above), otherwise
+  the packet latency will grow so large as to trigger timeouts in the TLS
+  layer and TCP connections running over the tunnel.
+
+  OpenVPN allows ``n`` to be between 100 bytes/sec and 100 Mbytes/sec.
+
+--inactive args
+  Causes OpenVPN to exit after ``n`` seconds of inactivity on the TUN/TAP
+  device. The time length of inactivity is measured since the last
+  incoming or outgoing tunnel packet. The default value is 0 seconds,
+  which disables this feature.
+
+  Valid syntaxes:
+  ::
+
+       inactive n
+       inactive n bytes
+
+  If the optional ``bytes`` parameter is included, exit if less than
+  ``bytes`` of combined in/out traffic are produced on the tun/tap device
+  in ``n`` seconds.
+
+  In any case, OpenVPN's internal ping packets (which are just keepalives)
+  and TLS control packets are not considered "activity", nor are they
+  counted as traffic, as they are used internally by OpenVPN and are not
+  an indication of actual user activity.
+
+--ping n
+  Ping remote over the TCP/UDP control channel if no packets have been
+  sent for at least ``n`` seconds (specify ``--ping`` on both peers to
+  cause ping packets to be sent in both directions since OpenVPN ping
+  packets are not echoed like IP ping packets). When used in one of
+  OpenVPN's secure modes (where ``--secret``, ``--tls-server`` or
+  ``--tls-client`` is specified), the ping packet will be
+  cryptographically secure.
+
+  This option has two intended uses:
+
+  (1)  Compatibility with stateful firewalls. The periodic ping will ensure
+       that a stateful firewall rule which allows OpenVPN UDP packets to
+       pass will not time out.
+
+  (2)  To provide a basis for the remote to test the existence of its peer
+       using the ``--ping-exit`` option.
+
+--ping-exit n
+  Causes OpenVPN to exit after ``n`` seconds pass without reception of a
+  ping or other packet from remote. This option can be combined with
+  ``--inactive``, ``--ping`` and ``--ping-exit`` to create a two-tiered
+  inactivity disconnect.
+
+  For example,
+  ::
+
+      openvpn [options...] --inactive 3600 --ping 10 --ping-exit 60
+
+  when used on both peers will cause OpenVPN to exit within 60 seconds if
+  its peer disconnects, but will exit after one hour if no actual tunnel
+  data is exchanged.
+
+--ping-restart n
+  Similar to ``--ping-exit``, but trigger a :code:`SIGUSR1` restart after
+  ``n`` seconds pass without reception of a ping or other packet from
+  remote.
+
+  This option is useful in cases where the remote peer has a dynamic IP
+  address and a low-TTL DNS name is used to track the IP address using a
+  service such as http://dyndns.org/ + a dynamic DNS client such as
+  ``ddclient``.
+
+  If the peer cannot be reached, a restart will be triggered, causing the
+  hostname used with ``--remote`` to be re-resolved (if ``--resolv-retry``
+  is also specified).
+
+  In server mode, ``--ping-restart``, ``--inactive`` or any other type of
+  internally generated signal will always be applied to individual client
+  instance objects, never to whole server itself. Note also in server mode
+  that any internally generated signal which would normally cause a
+  restart, will cause the deletion of the client instance object instead.
+
+  In client mode, the ``--ping-restart`` parameter is set to 120 seconds
+  by default. This default will hold until the client pulls a replacement
+  value from the server, based on the ``--keepalive`` setting in the
+  server configuration. To disable the 120 second default, set
+  ``--ping-restart 0`` on the client.
+
+  See the signals section below for more information on :code:`SIGUSR1`.
+
+  Note that the behavior of ``SIGUSR1`` can be modified by the
+  ``--persist-tun``, ``--persist-key``, ``--persist-local-ip`` and
+  ``--persist-remote-ip`` options.
+
+  Also note that ``--ping-exit`` and ``--ping-restart`` are mutually
+  exclusive and cannot be used together.
+
+--keepalive args
+  A helper directive designed to simplify the expression of ``--ping`` and
+  ``--ping-restart``.
+
+  Valid syntax:
+  ::
+
+     keepalive interval timeout
+
+  This option can be used on both client and server side, but it is enough
+  to add this on the server side as it will push appropriate ``--ping``
+  and ``--ping-restart`` options to the client. If used on both server and
+  client, the values pushed from server will override the client local
+  values.
+
+  The ``timeout`` argument will be twice as long on the server side. This
+  ensures that a timeout is detected on client side before the server side
+  drops the connection.
+
+  For example, ``--keepalive 10 60`` expands as follows:
+  ::
+
+     if mode server:
+         ping 10                    # Argument: interval
+         ping-restart 120           # Argument: timeout*2
+         push "ping 10"             # Argument: interval
+         push "ping-restart 60"     # Argument: timeout
+     else
+         ping 10                    # Argument: interval
+         ping-restart 60            # Argument: timeout
+
+--ping-timer-rem
+  Run the ``--ping-exit`` / ``--ping-restart`` timer only if we have a
+  remote address. Use this option if you are starting the daemon in listen
+  mode (i.e. without an explicit ``--remote`` peer), and you don't want to
+  start clocking timeouts until a remote peer connects.
+
+--persist-tun
+  Don't close and reopen TUN/TAP device or run up/down scripts across
+  :code:`SIGUSR1` or ``--ping-restart`` restarts.
+
+  :code:`SIGUSR1` is a restart signal similar to :code:`SIGHUP`, but which
+  offers finer-grained control over reset options.
+
+--persist-key
+  Don't re-read key files across :code:`SIGUSR1` or ``--ping-restart``.
+
+  This option can be combined with ``--user nobody`` to allow restarts
+  triggered by the :code:`SIGUSR1` signal. Normally if you drop root
+  privileges in OpenVPN, the daemon cannot be restarted since it will now
+  be unable to re-read protected key files.
+
+  This option solves the problem by persisting keys across :code:`SIGUSR1`
+  resets, so they don't need to be re-read.
+
+--persist-local-ip
+  Preserve initially resolved local IP address and port number across
+  ``SIGUSR1`` or ``--ping-restart`` restarts.
+
+--persist-remote-ip
+  Preserve most recently authenticated remote IP address and port number
+  across :code:`SIGUSR1` or ``--ping-restart`` restarts.
+
+--mlock
+  Disable paging by calling the POSIX mlockall function. Requires that
+  OpenVPN be initially run as root (though OpenVPN can subsequently
+  downgrade its UID using the ``--user`` option).
+
+  Using this option ensures that key material and tunnel data are never
+  written to disk due to virtual memory paging operations which occur
+  under most modern operating systems. It ensures that even if an attacker
+  was able to crack the box running OpenVPN, he would not be able to scan
+  the system swap file to recover previously used ephemeral keys, which
+  are used for a period of time governed by the ``--reneg`` options (see
+  below), then are discarded.
+
+  The downside of using ``--mlock`` is that it will reduce the amount of
+  physical memory available to other applications.
+
+--up cmd
+  Run command ``cmd`` after successful TUN/TAP device open (pre ``--user``
+  UID change).
+
+  ``cmd`` consists of a path to script (or executable program), optionally
+  followed by arguments. The path and arguments may be single- or
+  double-quoted and/or escaped using a backslash, and should be separated
+  by one or more spaces.
+
+  The up command is useful for specifying route commands which route IP
+  traffic destined for private subnets which exist at the other end of the
+  VPN connection into the tunnel.
+
+  For ``--dev tun`` execute as:
+  ::
+
+      cmd tun_dev tun_mtu link_mtu ifconfig_local_ip ifconfig_remote_ip [init | restart]
+
+  For ``--dev tap`` execute as:
+  ::
+
+       cmd tap_dev tap_mtu link_mtu ifconfig_local_ip ifconfig_netmask [init | restart]
+
+  See the `Environmental Variables`_ section below for additional
+  parameters passed as environmental variables.
+
+  Note that if ``cmd`` includes arguments, all OpenVPN-generated arguments
+  will be appended to them to build an argument list with which the
+  executable will be called.
+
+  Typically, ``cmd`` will run a script to add routes to the tunnel.
+
+  Normally the up script is called after the TUN/TAP device is opened. In
+  this context, the last command line parameter passed to the script will
+  be *init.* If the ``--up-restart`` option is also used, the up script
+  will be called for restarts as well. A restart is considered to be a
+  partial reinitialization of OpenVPN where the TUN/TAP instance is
+  preserved (the ``--persist-tun`` option will enable such preservation).
+  A restart can be generated by a SIGUSR1 signal, a ``--ping-restart``
+  timeout, or a connection reset when the TCP protocol is enabled with the
+  ``--proto`` option. If a restart occurs, and ``--up-restart`` has been
+  specified, the up script will be called with *restart* as the last
+  parameter.
+
+  *NOTE:*
+     On restart, OpenVPN will not pass the full set of environment
+     variables to the script. Namely, everything related to routing and
+     gateways will not be passed, as nothing needs to be done anyway - all
+     the routing setup is already in place. Additionally, the up-restart
+     script will run with the downgraded UID/GID settings (if configured).
+
+  The following standalone example shows how the ``--up`` script can be
+  called in both an initialization and restart context. (*NOTE:* for
+  security reasons, don't run the following example unless UDP port 9999
+  is blocked by your firewall. Also, the example will run indefinitely, so
+  you should abort with control-c).
+
+  ::
+
+      openvpn --dev tun --port 9999 --verb 4 --ping-restart 10 \
+              --up 'echo up' --down 'echo down' --persist-tun  \
+              --up-restart
+
+  Note that OpenVPN also provides the ``--ifconfig`` option to
+  automatically ifconfig the TUN device, eliminating the need to define an
+  ``--up`` script, unless you also want to configure routes in the
+  ``--up`` script.
+
+  If ``--ifconfig`` is also specified, OpenVPN will pass the ifconfig
+  local and remote endpoints on the command line to the ``--up`` script so
+  that they can be used to configure routes such as:
+
+  ::
+
+      route add -net 10.0.0.0 netmask 255.255.255.0 gw $5
+
+--up-delay
+  Delay TUN/TAP open and possible ``--up`` script execution until after
+  TCP/UDP connection establishment with peer.
+
+  In ``--proto udp`` mode, this option normally requires the use of
+  ``--ping`` to allow connection initiation to be sensed in the absence of
+  tunnel data, since UDP is a "connectionless" protocol.
+
+  On Windows, this option will delay the TAP-Win32 media state
+  transitioning to "connected" until connection establishment, i.e. the
+  receipt of the first authenticated packet from the peer.
+
+--down cmd
+  Run command ``cmd`` after TUN/TAP device close (post ``--user`` UID
+  change and/or ``--chroot`` ). ``cmd`` consists of a path to script (or
+  executable program), optionally followed by arguments. The path and
+  arguments may be single- or double-quoted and/or escaped using a
+  backslash, and should be separated by one or more spaces.
+
+  Called with the same parameters and environmental variables as the
+  ``--up`` option above.
+
+  Note that if you reduce privileges by using ``--user`` and/or
+  ``--group``, your ``--down`` script will also run at reduced privilege.
+
+--down-pre
+  Call ``--down`` cmd/script before, rather than after, TUN/TAP close.
+
+--up-restart
+  Enable the ``--up`` and ``--down`` scripts to be called for restarts as
+  well as initial program start. This option is described more fully above
+  in the ``--up`` option documentation.
+
+--setenv args
+  Set a custom environmental variable :code:`name=value` to pass to script.
+
+  Valid syntaxes:
+  ::
+
+     setenv name value
+     setenv FORWARD_COMPATIBLE 1
+     setenv opt config_option
+
+  By setting :code:`FORWARD_COMPATIBLE` to :code:`1`, the config file
+  syntax checking is relaxed so that unknown directives will trigger a
+  warning but not a fatal error, on the assumption that a given unknown
+  directive might be valid in future OpenVPN versions.
+
+  This option should be used with caution, as there are good security
+  reasons for having OpenVPN fail if it detects problems in a config file.
+  Having said that, there are valid reasons for wanting new software
+  features to gracefully degrade when encountered by older software
+  versions.
+
+  It is also possible to tag a single directive so as not to trigger a
+  fatal error if the directive isn't recognized. To do this, prepend the
+  following before the directive: ``setenv opt``
+
+  Versions prior to OpenVPN 2.3.3 will always ignore options set with the
+  ``setenv opt`` directive.
+
+  See also ``--ignore-unknown-option``
+
+--setenv-safe args
+  Set a custom environmental variable :code:`OPENVPN_name` to :code:`value`
+  to pass to scripts.
+
+  Valid syntaxes:
+  ::
+
+     setenv-safe name value
+
+  This directive is designed to be pushed by the server to clients, and
+  the prepending of :code:`OPENVPN_` to the environmental variable is a
+  safety precaution to prevent a :code:`LD_PRELOAD` style attack from a
+  malicious or compromised server.
+
+--ignore-unknown-option args
+  Valid syntax:
+  ::
+
+     ignore-unknown-options opt1 opt2 opt3 ... optN
+
+  When one of options ``opt1 ... optN`` is encountered in the configuration
+  file the configuration file parsing does not fail if this OpenVPN version
+  does not support the option. Multiple ``--ignore-unknown-option`` options
+  can be given to support a larger number of options to ignore.
+
+  This option should be used with caution, as there are good security
+  reasons for having OpenVPN fail if it detects problems in a config file.
+  Having said that, there are valid reasons for wanting new software
+  features to gracefully degrade when encountered by older software
+  versions.
+
+  ``--ignore-unknown-option`` is available since OpenVPN 2.3.3.
+
+--script-security level
+  This directive offers policy-level control over OpenVPN's usage of
+  external programs and scripts. Lower ``level`` values are more
+  restrictive, higher values are more permissive. Settings for ``level``:
+
+  :code:`0`
+      Strictly no calling of external programs.
+
+  :code:`1`
+      (Default) Only call built-in executables such as ifconfig,
+      ip, route, or netsh.
+
+  :code:`2`
+      Allow calling of built-in executables and user-defined
+      scripts.
+
+  :code:`3`
+      Allow passwords to be passed to scripts via environmental
+      variables (potentially unsafe).
+
+  OpenVPN releases before v2.3 also supported a ``method`` flag which
+  indicated how OpenVPN should call external commands and scripts. This
+  could be either :code:`execve` or :code:`system`. As of OpenVPN 2.3, this
+  flag is no longer accepted. In most \*nix environments the execve()
+  approach has been used without any issues.
+
+  Some directives such as ``--up`` allow options to be passed to the
+  external script. In these cases make sure the script name does not
+  contain any spaces or the configuration parser will choke because it
+  can't determine where the script name ends and script options start.
+
+  To run scripts in Windows in earlier OpenVPN versions you needed to
+  either add a full path to the script interpreter which can parse the
+  script or use the ``system`` flag to run these scripts. As of OpenVPN
+  2.3 it is now a strict requirement to have full path to the script
+  interpreter when running non-executables files. This is not needed for
+  executable files, such as .exe, .com, .bat or .cmd files. For example,
+  if you have a Visual Basic script, you must use this syntax now:
+
+  ::
+
+     --up 'C:\\Windows\\System32\\wscript.exe C:\\Program\ Files\\OpenVPN\\config\\my-up-script.vbs'
+
+  Please note the single quote marks and the escaping of the backslashes
+  (\\) and the space character.
+
+  The reason the support for the :code:`system` flag was removed is due to
+  the security implications with shell expansions when executing scripts
+  via the :code:`system()` call.
+
+--disable-occ
+  Don't output a warning message if option inconsistencies are detected
+  between peers. An example of an option inconsistency would be where one
+  peer uses ``--dev tun`` while the other peer uses ``--dev tap``.
+
+  Use of this option is discouraged, but is provided as a temporary fix in
+  situations where a recent version of OpenVPN must connect to an old
+  version.
+
+--user user
+  Change the user ID of the OpenVPN process to ``user`` after
+  initialization, dropping privileges in the process. This option is
+  useful to protect the system in the event that some hostile party was
+  able to gain control of an OpenVPN session. Though OpenVPN's security
+  features make this unlikely, it is provided as a second line of defense.
+
+  By setting ``user`` to :code:`nobody` or somebody similarly unprivileged,
+  the hostile party would be limited in what damage they could cause. Of
+  course once you take away privileges, you cannot return them to an
+  OpenVPN session. This means, for example, that if you want to reset an
+  OpenVPN daemon with a :code:`SIGUSR1` signal (for example in response to
+  a DHCP reset), you should make use of one or more of the ``--persist``
+  options to ensure that OpenVPN doesn't need to execute any privileged
+  operations in order to restart (such as re-reading key files or running
+  ``ifconfig`` on the TUN device).
+
+--group group
+  Similar to the ``--user`` option, this option changes the group ID of
+  the OpenVPN process to ``group`` after initialization.
+
+--cd dir
+  Change directory to ``dir`` prior to reading any files such as
+  configuration files, key files, scripts, etc. ``dir`` should be an
+  absolute path, with a leading "/", and without any references to the
+  current directory such as :code:`.` or :code:`..`.
+
+  This option is useful when you are running OpenVPN in ``--daemon`` mode,
+  and you want to consolidate all of your OpenVPN control files in one
+  location.
+
+--chroot dir
+  Chroot to ``dir`` after initialization. ``--chroot`` essentially
+  redefines ``dir`` as being the top level directory tree (/). OpenVPN
+  will therefore be unable to access any files outside this tree. This can
+  be desirable from a security standpoint.
+
+  Since the chroot operation is delayed until after initialization, most
+  OpenVPN options that reference files will operate in a pre-chroot
+  context.
+
+  In many cases, the ``dir`` parameter can point to an empty directory,
+  however complications can result when scripts or restarts are executed
+  after the chroot operation.
+
+  Note: The SSL library will probably need /dev/urandom to be available
+  inside the chroot directory ``dir``. This is because SSL libraries
+  occasionally need to collect fresh random. Newer linux kernels and some
+  BSDs implement a getrandom() or getentropy() syscall that removes the
+  need for /dev/urandom to be available.
+
+--setcon context
+  Apply SELinux ``context`` after initialization. This essentially
+  provides the ability to restrict OpenVPN's rights to only network I/O
+  operations, thanks to SELinux. This goes further than ``--user`` and
+  ``--chroot`` in that those two, while being great security features,
+  unfortunately do not protect against privilege escalation by
+  exploitation of a vulnerable system call. You can of course combine all
+  three, but please note that since setcon requires access to /proc you
+  will have to provide it inside the chroot directory (e.g. with mount
+  --bind).
+
+  Since the setcon operation is delayed until after initialization,
+  OpenVPN can be restricted to just network-related system calls, whereas
+  by applying the context before startup (such as the OpenVPN one provided
+  in the SELinux Reference Policies) you will have to allow many things...
 
[truncated message content]