ubuntu 12.04 ipsec server problem. Help needed

Hi
I follow this guide to setup IPSEC/L2TP https://raymii.org/s/tutorials/IPSEC_L2TP_vpn_with_Ubuntu_12.04.html
However, when I set it up in Windows as a client, I cannot connect to the server. I look at syslog, it says it is listening on port 1701
But using netstat -a , port 1701 is not open. xl2tpd do show up in ps -A.
So I am very confusing where is the problem.