pre-install OpenVPN question

[DutchMike]

I recently bought an Asus RT AC68U router and it all seems to work fine, but has one nasty little habbit.
I have a Synology DS214play NAS, which contains my data and a Synology DS115J at my parents house on which I store my backup.
My local IP-ranges is 192.168.0.x, the IP-range at my parents hous is: 192.168.2.x and the VPN IP-range is 10.8.0.x

Between the DS115J and the Asus is an OpenVPN connection, which is functioning very well. The only problem with the default firmware is, that the VPN-IP-adress changes per time the connection is (re-)established. The connection is always on, but when the connection is lost, the router assigns a differtend IP-adress to the DS115J when the connection is online again.
The daily backup is not working at irregular intervals, when the VPN IP is changed, so I have to check it every day to see if it has changed.

My question is there a way in the Asuswrt-Merlin-firmware to assign an fixed VPN IP-adress to a device?

 

[ColinTaylor]

Can you clarify;
Is the VPN at your parents' house running on the DS115J or their router?
At your end presumably you're running the VPN on your AC68U. Is that a VPN client or a VPN server?

 

[Martineau]

My question is there a way in the Asuswrt-Merlin-firmware to assign an fixed VPN IP-adress to a device?

Yes.

So when the DS115J connects as a VPN Client to your RT-AC68U hosting the OpenVPN Server, then you can use the CCD file to assign a static IP Address from the appropriate OpenVPN Server IP pool.
How to set a static IP to OpenVPN TUN clients

NOTE: If your RT-AC68U is the client then the CCD static IP configuration will be on the router at your parents.

 

[DutchMike]

thank you both for your reply!
The OpenVPN-server is running on my Asus RT AC68U and the Synology DS115J is the client of the Asus RT AC68U.

I'm going to check out the link you gave me @Martineau and will give it a try shortly!