This post shows how to setup an ipsec VPN connection in roadwarrior fashion. Roadwarrior mode is where you typically have a mobile device which has a dynamic address and you want to connect back to a VPN server. This post uses a simple pre shared key to establish the VPN connection using strongswan. This is much simpler than my past openswan approach which also relied on L2TP, Pluto etc. needing to be configured. Performance also seems to be better with VPN connections establishing much faster.