My friend has a router, and she wants me to login his router to config something from time to time. Because it's difficult to apply a free domain. So it's not a good idea to config her router as a VPN server. It's feasible to config her router as a VPN client and connect my router. The problem is: if her route is connected as a VPN client of my router's, all her network traffic will go through my network. That's too bad. I just want: 1. I can login her router in my network. For example, when I'm at home, or I connect my router through the VPN. 2. Her network traffic will not go through my router. Otherwise the network will become slow for both her and me. Any idea?