Using OpenVPN to connect to a device on a 3G network

pldevrie

Hi,

I'm trying to find a solution to connect to devices that we have installed by customers that are connected to networks for mobile communications (like GPRS or UMTS). Normally on a fixed network we could just create a port-forward in the cliensts router, and connect to that, but in this case this is not possible, as mobile networks have their incomming ports closed.

So what I want to do is to place an openVPN enabled router on the mobile network, en let it connect to an openVPN server at our office. Then using the openVPN connection I want to be able to connect to the devices connected to this router at the customers site.

As a router I have a TP-link 1043ND flashed with DD-WRT, and as a server I'm using a QNAP NAS (TS 259). Using a tutorial I got these two connecting to each other, but I'm stuck now.

My guess is that I need to setup some route in the OpenVPN-server and/or in the OpenVPN-client, but I haven't got a clue how to do this.

So I hope someone can point me in the right direction, (or suggest a different/better solution..)

Thanks in advance,
Peter

janjust

first make sure one of the clients can connect to the OpenVPN server;
make sure the client can ping other hosts on the server side LAN and vice versa;
then open up a port on the client PC: this port should now be accessible from the VPN server using the VPN client IP.
make sure the port is also accessible from other hosts in the LAN

after step 1 it is all a matter or routing, really.

pldevrie

Hi,
I just picked this up again.
1) seems to be ok.
Server gets ip: 10.8.0.1 P-t-P:10.8.0.2 Mask:255.255.255.255
Client gets ip: 10.8.0.6 P-t-P:10.8.0.5 Mask:255.255.255.255 (one of two clients)
2) Here the problems start.
Client can ping to 10.8.0.1 and 10.8.0.6
Server can only ping 10.8.0.1
The cannot ping anything on the 192.168.1.0/24 network (server side LAN)

I understand the rest is a matter of routing, but here I need some clues as I'm a newby to this.
I do have

push "route 192.168.1.0 255.255.255.0"

in my server script, and

pull

in my client script.

Also how do I need to setup the client side of the OpenVPN-Client? I now use a 192.168.x.0/24 setup, where x is different for each client, and different from the server-side LAN. Is that the right way to do this?

janjust

2) Here the problems start.
Client can ping to 10.8.0.1 and 10.8.0.6
Server can only ping 10.8.0.1

if the client can ping the server but not vice versa then there's a firewall on the client blocking access....

push "route 192.168.1.0 255.255.255.0"

this tells the client to route all traffic for 192.168.1.0/24 over the VPN - verify that that IS what you want.
Does the server-side LAN know that traffic coming from 10.8.0.x needs to go back to the VPN server, i.e. is there a route on the LAN GW

route -net 10.8.0.0/24 gw <LAN-IP-of-server>