Openvpn

My previous posts (http://nkush.blogspot.com.au/2012/08/installing-openvpn-22-on-centos-63-64bit.html and http://nkush.blogspot.com.au/2011/10/installing-openvpn-22-on-centos-57.html) have been on installing OpenVPN on Linux.

This post is slightly different as it installs and configures OpenVPN on a Microsoft Windows Small Business Server (SBS). The SBS installation is also different from the previous write-ups since this configuration uses Ethernet bridging instead of tunneling.

Although SBS comes with Layer2 Tunneling Protocol (L2TP) and Point-to-point Tunelling Protocol (PPTP) for Virtual Private Network (VPN), some users may want to use an Secure Sockets Layer (SSL) based VPN such as OpenVPN. The default installation location, i.e. C:\Program Files\OpenVPN\ is used in the instructions below

To connect to an OpenVPN server you need an appropriate OpenVPN client installed to establish the SSL link. For Apple Mac OS X systems, TunnelBlick (http://code.google.com/p/tunnelblick/) is a good graphical user interface. At the time of this blog the current latest stable version of TunnelBlick available was 3.2.7. These instructions were executed on an Apple iMac running Mac OS X 10.7.4. As with all other posts on this blog, the purpose of this post is not to provide a tutorial, but instead to documents the steps taken, for my own benefit.

This post is just an update of a previous post that used CentOS 5.7 and OpenVPN 2.2 (http://nkush.blogspot.com.au/2011/10/installing-openvpn-22-on-centos-57.html). The basic instructions are the same, however this post uses some newer packages which may have been relocated to new URLs. Again this blog and the posts are mostly for my own reference and not intended as step-by-step instuctions for other systems/network administrators

Install RPMForge or RepoForge as it’s now known[1]

OpenVPN is an SSL based VPN. There are other VPN solutions such as IPsec, etc. but OpenVPN provides a cost effective alternative. I like OpenVPN as it support two-way authentication, i.e. both the client and server authenticate using certificates. To install OpeVPN on CentOS we need a number of cryptographic libraries. The simplest way is to use the DAG/RPMForge repository.

Set-up the RPMForge repository [1], as this contains the packages necessary for the installation and the instructions are provided below. The instructions below are just to document this specific installation and therefore this blog post is not to be misinterpreted as a best practises guide. The instructions are adapted from the OpenVPN website [2], but this blog post is intended more as a quick and dirty guide to getting OpenVPN running on CentOS 5.7. Additionally the set-up and configuration of the client is considered beyond the scope of this blog post.