ipsec of ros
１主服务内网地址、远端内网地址；主服务公网地址，远端公网地址；
2 设置共享pre shared key；设置加密3des、加密组、hash；主模式，远端公网地址；
3 数据加密 md5 3des;
4 nat之前accecpt 源：服务内网地址 目的：远端内网地址;
5 route 远端内网地址------>服务端公网ip------>wan口
ipsec of juniper
主服务端设置
1gateway: remote gateway static ip address;
2preshare key : key interface phase 1 main;
3IKE: remote gateway predefine phase 2;
4police: source:erp server destination:remote private address port:erp tunnel predefine
L2TP
1 mode l2tp user password address to remote client;
2 l2tp tunnel outgoing interface;
3 police : source:dial-up *** destination:erp server port:erp