====== VPN ======

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====== VPN Command for Linux ======


<code>openvpn --verb 9 --dev tun0 --config /etc/openvpn/client.conf</code>

====== VPN Information and Setup ======

[[http://openvpn.net/index.php/open-source.html|OpenVPN Community]]

[[http://en.opensuse.org/Yet_another_OpenVPN_bridged_mode_setup_howto|OpenVpn Bridged]]

[[http://www.jacco2.dds.nl/networking/freeswan-panther.html|OpenSwan and Mac]] and 

[[http://www.jacco2.dds.nl/networking/freeswan-l2tp.html]]

[[http://lists.openswan.org/pipermail/users/2009-July/017098.html|Connection Drops]]

[[http://akutz.wordpress.com/2007/12/09/connecting-to-openswan-with-os-x-leopard-1051/|Connecting discussion]]

[[http://articles.techrepublic.com.com/2415-1035_11-163244.html|Microsoft provides Mac users with a free Remote Desktop Connection Client For Mac application]]

[[http://techrepublic.com.com/5208-6230-0.html?forumID=102&amp;threadID=225753&amp;messageID=2253813&amp;tag=content;leftCol|OpenVPN and the Tunnelblick]]

[[http://lists.openswan.org/pipermail/users/2008-April/014479.html|[Openswan Users] Mac OS X can't connect to Openswan server (Linux Kernel 2.6)]]

[[http://wiki.openswan.org/index.php/Interop/InteroperatingMac|Interoperating: Mac OS X]]

====== Ciphers ======

[[http://people.mandriva.com/%7Eybourhis/openvpn/index.html|http://people.mandriva.com/ybourhis/openvpn/index.html]]

<code>The following ciphers and cipher modes are available
for use with OpenVPN.  Each cipher shown below may be
used as a parameter to the --cipher option.  The default
key size is shown as well as whether or not it can be
changed with the --keysize directive.  Using a CBC mode
is recommended.

DES-CBC 64 bit default key (fixed)
IDEA-CBC 128 bit default key (fixed)
RC2-CBC 128 bit default key (variable)
DES-EDE-CBC 128 bit default key (fixed)
DES-EDE3-CBC 192 bit default key (fixed)
DESX-CBC 192 bit default key (fixed)
BF-CBC 128 bit default key (variable)
RC2-40-CBC 40 bit default key (variable)
CAST5-CBC 128 bit default key (variable)
RC5-CBC 128 bit default key (variable)
RC2-64-CBC 64 bit default key (variable)
AES-128-CBC 128 bit default key (fixed)
AES-192-CBC 192 bit default key (fixed)
AES-256-CBC 256 bit default key (fixed)</code>

====== openVPN ======

  * Throughput/Performance
  * VPNs require encryption/decryption of traffic and that takes CPU cycles. 
  * One of the important measures of a VPN is its throughput or the amount of data is can pass before it is unable to keep up with the decrypt/encrypt activities. With hardware VPNs this is an easy number to find, but with software products like OpenVPN, your throughput will depend a lot on your hardware. 
  * For this document, OpenVPN was tested with a **Pentium III 1Ghz machine with 512K** RAM running Gentoo Linux. 
  * The other end of the tunnel was a Pentium IV 2.7 GHz machine running Windows XP. 
  * The link between these two machines max's out at **3 Mbps** and OpenVPN was able to keep up with this load without any degradation in throughput. 
  * The processor loads on both sides were miniscule and while one should not expect OpenVPN to scale linearly, it should handle enough throughput to service most small to medium-sized implementations, and with load balancing or more serious hardware, it could handle many larger implementations as well. 
  * Additionally, there is the very real possibility that OpenVPN can benefit from the myriad of hardware SSL accelerator cards out there as it is using the standard SSL/TLS functions. (Check the OpenVPN user mailing list for more information). 
  * OpenVPN does not have a hard limit to the number of tunnels it can sustain.