anchor.diff:  
   Successful configuration of the Yubico PAM module to support two factor authentication for OpenVPN has the following prerequisites:
   
  -  * Operating System: Any Unix operating system which supports PAM (Pluggable Authentication Module)
  -    (http://www.kernel.org/pub/linux/libs/pam/)
  -  * Complier : GNU GCC complier (http://gcc.gnu.org/)
  -  * Yubico PAM Module: Yubico PAM Module Version 1.8. (https://developers.yubico.com/yubico-pam/)
  -  * OpenVPN: OpenVPN Version 2.0.9. (http://openvpn.net/index.php/downloads.html)
  -  * FreeRADIUS: FreeRADIUS Version: 1.1.7 or later. (http://freeradius.org/download.html)
  -  * Pam_Radius: pam_radius Version 1.3.17. (ftp://ftp.freeradius.org/pub/radius/pam_radius-1.3.17.tar.gz)
  +Operating System:: 
  +Any Unix operating system which supports 
  +http://www.kernel.org/pub/linux/libs/pam[PAM] (Pluggable Authentication Module)
  +Complier:: http://gcc.gnu.org[GNU GCC complier]
  +https://developers.yubico.com/yubico-pam[Yubico PAM Module]:: Version 1.8
  +http://openvpn.net/index.php/downloads.html[OpenVPN]:: Version 2.0.9.
  +http://freeradius.org/download.html[FreeRADIUS]: Version 1.1.7 or later.
  +Pam_Radius:: ftp://ftp.freeradius.org/pub/radius/pam_radius-1.3.17.tar.gz[Version 1.3.17].
   
   Configuration
   -------------
  
positive.code: b) Installation of pam_yubico module:
  -------------------------------------
  
  Build instructions for pam_yubico are available in the README:
  
  https://github.com/Yubico/yubico-pam/wiki/ReadMe
  
  c) Configuration of pam_yubico module:
  --------------------------------------
  
negative.code: Please use the following command for testing:
  
  ------
  [root@testsrv ~]# openvpn /etc/openvpn/client.conf
  ------
  
  OpenVPN client will first prompt for username, enter the username.
  