平台:DigitalOcean VPS原生ubuntu14.04 x86, strongswan5.1.3
apt-get install build-essential #编译环境
aptitude install libgmp10 libgmp3-dev libssl-dev pkg-config libpcsclite-dev libpam0g-dev #编译所需要的软件
strongswan官网 http://www.strongswan.org/ , 5.2.0版本地址 http://download.strongswan.org/strongswan-5.2.0.tar.bz2
wget http://download.strongswan.org/strongswan-5.2.0.tar.bz2