First, there is a picture of my lan: What i want to do is, should be, easy. Between Network 1 and Main Network, i have a BEFSR41 to allow Network 2 to talk to main network. But the reverse is not possible because the SR41 is doing NAT. In the SR41, there is a "Gateway" and a "Router" mode. For NAT, I have to set it as gateway. If i put it in Router mode, those 2 network (Main and 1) can access each other. But, in that mode, Network 1 cant acces the internet. Why?