To use the VPN service provided by ItsHidden.com, complete the following steps (that were partially found in this Ubuntu forum thread): 要使用itsHidden.com提供的VPN服务，请根据下面的步骤操作： Install the PPTP plug-in for Network Manager//安装nm的PPTP插件$ sudo apt-get install network-manager-pptp Restart Network Manager//重启NM服务 $ sudo killall NetworkManager && sudo NetworkManager & Create the VPN connection //创建VPN链接 In the “Advanced…” settings, enable “Use Point-to-Point encryption (MPPE)”//在VPN创建窗口，点击“高级”，勾选“使用点对点加密”