ASUS rt56u, merlin 384.6 - routing to vpn only based on destination address

[Chris Pazz]

Hi,
I have an Asus rt56u with latest merlin.

I have configured an OpenVPN client for my vpn provider (nordvpn).
I have 2 clients on network that are using a specific service connecting to an external destination address (for eg. 100.100.100.100) and I need to route only those specific connection via VPN (with killswitch enabled).

First one is a Fire TV Stick and second one is a single Docker container running in my Synology NAS (host mode).

Both of them do not have to be routed fully via vpn. The NAS is used also for serving some services (web, ecc..) so cannot be all via VPN, The fire TV Stick has some services that, if routed, raise geo licensing problems.

How can I set up routing policies so that all connection works the same via WAN but the connection from those 2 clients to 100.100.100.100 go via VPN?

I have tried to insert a single policy rule:

0.0.0.0 as source, 100.100.100.100 as destination -> VPN

but it seems to route all my network thru VPN. Also setting up the 2 lan clients IP as source address seems not to take care of destination address causing all network from them to be routed via VPN.

I can also evaluate other solutions if there is any way to install on my synology NAS a vpn gateway or something similar (via docker).

Thank you
Chris