Can only see router, not router's devices through OpenVPN

scottn · 2017-04-06T00:18:56.000Z

I am trying to set up remote access from my office to a piece of hardware in the field that is connected to the LAN port of my GL-AR300M. I cannot simply forward ports to it since the communication I need relies on broadcast messages. I thought that a VPN would easily solve this. I am far from an expert at networking and have spent many days trying to dial in this configuration. I’m at my wits end and desperately need help from others much smarter than me in the community!

I installed an OpenVPN server on my office machine, and have set up the OpenVPN client on the GL-AR300M in the field. The VPN connection works fine (I can connect directly to the GL-AR300M), but i cannot figure out how to get to my device which is plugged into the GL-AR300M’s LAN port.

I tried configuring the advanced router settings in Luci and bridging the VPN-Client adapter with the eth0 adapter. This doesn’t work and just breaks the VPN.

The OpenVPN server’s IP is 192.168.8.1. I’ve got it configured as TAP

The OpenVPN Client’s IP is 192.168.8.2. Like i said i can connect with this device as if it were right here in my office.

The device that I need to connect to is plugged into the LAN port of the GL-AR300M with an IP address of 192.168.8.3

I can SSH into the GL-AR300M and ping 192.168.8.3, but i cannot ping it from my local machine.

Please help!

alzhao · 2017-04-06T10:41:44.000Z

There is a problem. You cannot use the same subnet for vpn and the router.

Your VPN server 8.1 and AR300M 8.2. You may need to change your AR300M’s subnet to 9.1 so that your device is 9.3, not 8.3.

You can also change your vpn sever’s IP to other IP address e.g. 9.1 etc. Don’t use 8.1 which is the same as AR300M’s own IP.

As AR300M has a firewall so you need to enable ACCEPT in AR300m’s VPN_client interface in firewall. You can do this in Luci or just using SSH.

Modify this file /etc/config/firewall, find VPN_client and add “option input ACCEPT” and “option forward ACCEPT”

May also need to add a new forwarding rule

config rule ‘my_forward’
option src ‘VPN_client’
option dest ‘lan’