Installation instructions for OpenVPN, a Secure Tunneling Daemon

Copyright (C) 2002-2005 OpenVPN Solutions LLC. This program is free software;
you can redistribute it and/or modify
it under the terms of the GNU General Public License version 2
as published by the Free Software Foundation.

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To download OpenVPN, go to:

	http://openvpn.net/download.html

For step-by-step installation instructions with real-world
examples see:

	http://openvpn.net/howto.html

For examples see:

	http://openvpn.net/examples.html

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SUPPORTED PLATFORMS:
  (1) Linux 2.2+
  (2) Solaris
  (3) OpenBSD 3.0+ (Comes with OpenSSL and TUN devices by default)
  (4) Mac OS X Darwin
  (5) FreeBSD
  (6) NetBSD
  (7) Windows (Win 2K and higher)

SUPPORTED PROCESSOR ARCHITECTURES:
   In general, OpenVPN is word size and endian independent, so
   most processors should be supported.  Architectures known to
   work include Intel x86, Alpha, Sparc, Amd64, and ARM.

REQUIRES:
  (1) TUN and/or TAP driver to allow user-space programs to control
      a virtual point-to-point IP or Ethernet device.  See
      TUN/TAP Driver Configuration section below for more info.

OPTIONAL (but recommended):
  (1) OpenSSL library, necessary for encryption, version 0.9.5 or higher
      required, available from http://www.openssl.org/
  (2) LZO real-time compression library, required for link compression,
      available from http://www.oberhumer.com/opensource/lzo/
      OpenBSD users can use ports or packages to install lzo, but remember
      to add "--with-lzo-headers" and "--with-lzo-lib" directives to
      "configure", pointing to /usr/local/include and /usr/local/lib
      respectively since gcc will not find them otherwise.
  (3) Pthread library.

OPTIONAL (for developers only):
  (1) Autoconf 2.50 or higher + Automake 1.5 or higher
      -- available from http://www.gnu.org/software/software.html
  (2) Dmalloc library
      -- available from http://dmalloc.com/

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BUILD COMMANDS FROM TARBALL:

	./configure
	make
	make install

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BUILD COMMANDS FROM CVS:

	autoreconf -i -v
	./configure
	make
	make install

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BUILD A TARBALL FROM CVS:

	autoreconf -i -v
	./configure
	make dist

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LOOPBACK TESTS (after BUILD):

make check (Run all tests below)

Test Crypto:

./openvpn --genkey --secret key
./openvpn --test-crypto --secret key

Test SSL/TLS negotiations (runs for 2 minutes):

./openvpn --config sample-config-files/loopback-client  (In one window) 
./openvpn --config sample-config-files/loopback-server  (Simultaneously in another window) 

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OPTIONS for ./configure:

  --enable-pthread          Compile pthread support for
                            improved latency during SSL/TLS key
                            negotiations (Linux or Solaris only)

  --disable-lzo             Do not compile LZO compression support
  --disable-crypto          Do not compile OpenSSL crypto support
  --disable-ssl             Do not compile OpenSSL SSL support for
                            TLS-based key exchange

  --with-ssl-headers=DIR    Crypto/SSL Include files location
  --with-ssl-lib=DIR        Crypto/SSL Library location
  --with-lzo-headers=DIR    LZO Include files location
  --with-lzo-lib=DIR        LZO Library location

  --with-ifconfig-path=PATH   Path to ifconfig tool (only need to
                              specify if in a non-standard location)

  --with-leak-check=TYPE    Build with memory leak checking
                            TYPE = dmalloc or ssl

  --enable-strict           Enable strict compiler warnings

  --enable-strict-options   Enable strict options check between peers

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BUILDING ON LINUX 2.4+ FROM RPM

You can build a binary RPM directly from the OpenVPN tarball file:

	rpmbuild -tb [tarball]

This command will build a binary RPM file and place it in the system
RPM directory.  You can then install the RPM with the standard RPM
install command:

	rpm -ivh [binary-rpm]

When you install the binary RPM, it will install
sample-scripts/openvpn.init, which can be used to
automatically start or stop one or more OpenVPN tunnels on system
startup or shutdown, based on OpenVPN .conf files in /etc/openvpn.
See the comments in openvpn.init for more information.

Installing the RPM will also configure the TUN/TAP device node
for linux 2.4.

Note that the current openvpn.spec file, which instructs the rpm tool
how to build a package, will build OpenVPN with all options enabled,
including OpenSSL, LZO, and pthread linkage.  Therefore all of
these packages will need to be present prior to the RPM build, unless
you edit the openvpn.spec file.

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TUN/TAP Driver Configuration:

* Linux 2.4 or higher (with integrated TUN/TAP driver):

  (1)  make device node:         mknod /dev/net/tun c 10 200
  (2a) add to /etc/modules.conf: alias char-major-10-200 tun
  (2b) load driver:              modprobe tun
  (3)  enable routing:           echo 1 > /proc/sys/net/ipv4/ip_forward

  Note that either of steps (2a) or (2b) is sufficient.  While (2a)
  only needs to be done once per install, (2b) needs to be done once
  per reboot.  If you install from RPM (see above) and use the
  openvpn.init script, these steps are taken care of for you.

* Linux 2.2 or Solaris:

  You should obtain
  version 1.1 of the TUN/TAP driver from
  http://vtun.sourceforge.net/tun/
  and follow the installation instructions.

  If you use OpenVPN on Linux 2.2 or 2.4 or Solaris, you may be
  suffering from a bug which causes connections to hang under heavy load.
  The symptoms are very similar to the MTU problems discussed frequently
  in the OpenVPN mailing lists. But it turns out that this bug is not caused by
  MTU problems. It's a bug in the tun/tap driver.  A patch is provided here:

  http://openvpn.net/patch/tun-sb.patch

* Solaris

  For 64 bit, I used the tun-1.1.tar.gz source and compiled it.

  Of course there is a but :)
  In the tun-1-1\solaris\Makefile I changed a line so it compiles with 64 bit

  CFLAGS = $(DEFS) -m64 -O2 -Wall -D_KERNEL -I.

  I just added -m64 and it worked.

  The tun driver works fine as said previously, however we noticed there is a
  minor problem when creating multiple tunnels on Solaris.
  Mr Tycho Fruru changed the code in tun.c file where he locked the tun device
  number to -1. This way it is impossible to specify the name of the tun device
  but it is still possible to have multiple devices.
  The modification will increment automatically meaning starting from tun0 --->
  tunX I know you are not responsible for the tun coding but if you think the
  modification can be useful for you feel free to use it.

  http://openvpn.net/solaris/tun.c

* FreeBSD 4.1.1+:

  FreeBSD ships with the TUN/TAP driver, and the device nodes for tap0,
  tap1, tap2, tap3, tun0, tun1, tun2 and tun3 are made by default.
  However, only the TUN driver is linked into the GENERIC kernel.

  To load the TAP driver, enter: 

	kldload if_tap

  See man rc(8) to find out how you can do this at boot time.

  The easiest way is to install OpenVPN from the FreeBSD ports system,
  the port includes a sample script to automatically load the TAP driver
  at boot-up time.

* OpenBSD:

  OpenBSD ships with tun0 and tun1 installed by default on pre-3.5 systems,
  while 3.5 and later have dynamically created tun* devices so you only need
  to create an empty /etc/hostname.tun0 (tun1, tun2 and so on) for each tun
  you plan to use to create the device(s) at boot.

* Mac OS X:

  2005.02.13: Angelo Laub has developed a GUI for OS X:

  http://rechenknecht.net/OpenVPN-GUI/

  2004.10.26: Mattias Nissler has developed a new TUN/TAP driver for
  MAC OS X:

  http://www-user.rhrk.uni-kl.de/~nissler/tuntap/    

  Christoph Pfisterer's old TUN driver can be obtained at
  http://chrisp.de/en/projects/tunnel.html -- note that it
  is no longer being maintained.

* Solaris9 Sparc/64

  The kernel module for solaris
  can be generated by adding the -m64 switch to a modern
  gcc compiler (I'm using 3.2)  The resulting kernel driver
  needs to be manually copied to /kernel/drv/sparcv9/ and then a 
  reconfiguration reboot. (boot -r).

* Windows 2000 and XP

  See INSTALL-win32.txt for more info

 See the man page for more information, usage examples, and
 information on firewall configuration.

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CAVEATS & BUGS:

* I have noticed cases where TCP sessions tunneled over the Linux
  TAP driver (kernel 2.4.21 and 2.4.22) stall when lower --mssfix
  values are used.  The TCP sessions appear to unstall and resume
  normally when the remote VPN endpoint is pinged.

* If run through a firewall using OpenBSDs packet filter PF and the
  filter rules include a "scrub" directive, you may get problems talking
  to Linux hosts over the tunnel, since the scrubbing will kill packets
  sent from Linux hosts if they are fragmented. This is usually seen as
  tunnels where small packets and pings get through but large packets
  and "regular traffic" don't. To circumvent this, add "no-df" to
  the scrub directive so that the packet filter will let fragments with
  the "dont fragment"-flag set through anyway.

* Mixing OFB or CFB cipher modes with static key mode is not recommended,
  and is flagged as an error on OpenVPN versions 1.2.1 and greater.
  If you use the --cipher option to explicitly select an OFB or CFB
  cipher AND you are using static key mode, it is possible that there
  could be an IV collision if the OpenVPN daemons on both sides
  of the connection are started at exactly the same time, since
  OpenVPN uses a timestamp combined with a sequence number as the cipher
  IV for OFB and CFB modes.  This is not an issue if you are
  using CBC cipher mode (the default), or if you are using OFB or CFB
  cipher mode with SSL/TLS authentication.
