GRE tunneling between two OpenWrt routers

Hello, I recently purchased 2 routers with OpenWRT firmware.

The idea is to create a GRE tunneling between those networks (different locations).

Main House (OpenWRT Router 1 attached to ISP router) <<< ETHERNET >>> Another House (OpenWRT Router 2 attached to another ISP router)

I need to connect a device to OpenWRT Router 2 and simulate that is connected physically to ISP Router 1 (because of multicast group)

How can I do that?


ipv4, ipv6 or both?

IPv4, but better if both are possible, thanks!

I guess you need gretap (Ethernet GRE tunnel over IPv4). The gretap on OpenWrt router 1 should be connected to the wan network. And gretap on OpenWrt router 2 should be connected to one of the lan ports which you have moved to a separate vlan in the router's vlan switch.

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Later I will try, thanks!

I did something similar, to extend several networks over the same wireless link, but I think you can adapt it to your needs: Trunking over wireless?

The destination IP address I have is the public address of the other side of the tunnel, but this is managed by the ISP router.

Do I need to setup a VPN connection (OpenVPN) to have access to the private IP addresses of House 1 from House 2?

If you’re going over the open Internet, be aware that GRE doesn’t provide encryption. For “as if you are there” you typically need a Layer 2 bridge. Simple tunneling approaches have MTU issues. VPNs that can provide Layer 2 tunneling are preferred by many.

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Yes, Layer 2 Bridge GRE is exactly I need:

Layer-2 GRE tunnels allow you to have the same VLAN in multiple locations (separated by a Layer-3 network) and be connected. The forwarding method for a Layer-2 GRE tunnel is bridging.


"House 2 Device" need to simulate that is in "House 1" to be able to join the multicast (video streaming). This is the only device that send/receive within the tunnel. Rest of devices and traffic in "House 2" are independent.

Yes I think running GRETAP over a routed vpn is a good idea. But I prefer wireguard instead of openvpn. (And I use GRE over wireguard as a way to access the Internet without adding to allowedips.)

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Wireguard is installed, I will test and learn about it. Thanks!

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