Installation instructions for OpenVPN, a Secure Tunneling Daemon

Copyright (C) 2002 by James Yonan. This program is free software;
you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

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For the latest stable version of OpenVPN, go to:

	http://sourceforge.net/projects/openvpn/

For the latest development version of OpenVPN, go to:

	http://openvpn.sourceforge.net/beta/

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

	http://openvpn.sourceforge.net/howto.html

For basic examples see:

	http://openvpn.sourceforge.net/man.html#lbAN

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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 (Experimental)
  (5) FreeBSD
  (6) NetBSD
  (7) Windows (Win 2K + XP only so far
      -- see INSTALL-win32.txt for more info)

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, 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):

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

  --enable-mtu-dynamic      Enable dynamic MTU support (experimental)

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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.

* 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.

* Mac OS X:

  Obtain Christoph Pfisterer's TUN driver at
  http://chrisp.de/en/projects/tunnel.html

* 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:

* OpenVPN works fine with the 1.1 TUN/TAP driver in the Linux 2.2 kernels,
  and with the integrated 1.4 TUN/TAP driver in the Linux 2.4 kernels, but
  there's a "gray area" in the 2.4 kernels before 2.4.7 where various
  things may break due to the TUN/TAP driver and other kernel components
  being in a state of flux, so I wouldn't recommend using OpenVPN on these
  kernels unless you are prepared to do some debugging and testing.

* Pthread support is not yet stable on OpenBSD or any platform that implements
  threads in user-space without supporting true preemptive scheduling
  between threads.  Pthread implementations which are compatible with Linux
  or Solaris implementations should work fine with OpenVPN.

* 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.

* 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.
