Originally Posted by sent2020
We are using Linux machine as a gateway server to connect our local network to wan. We use pptp vpn to connect our remote customers network, is it possible to connect VPN to the gateway and make local network to connect through it? so that there is no need to connect vpn in every local client.
Please share your views.
Yes, that's very doable. Since you're already making the site-to-site connection via VPN, all you've really got to do is add a network route on either side. You've already done the hard work, and I'm going to assume that you've got Linux boxes on BOTH sides of things.
So sitea will have (for example) a network of 192.168.100.0 and siteb will have 192.168.200.0. On the VPN box at sitea, add a network route to 192.168.200.0 using the gateway of your VPN address. Reverse the process at siteb. That way, if someone at sitea does a "ping 192.168.200.33", the Linux VPN box will route it through the VPN tunnel, taking care of the NAT'ing etc., to make it work.
EDIT: One more thing: you will have to enable IP forwarding on both VPN gateways, too.