I've a Synology NAS, the DS218+, and i have this setup:
The NAS is connectet to my router (AVM FritzBox), which is the ISP device that is connected to the internet
On this router, i set up a DynDNS service, in order to access my home network over the internet
On the NAS, i configured an OpenVPN connection using my VPN provider, in order to get secure internet access for the NAS services (not a VPN server, the NAS is the VPN Client here)
Each of this things for itself works fine - but not in combination:
If the VPN connection on the NAS is active, i can't access it using DynDNS
If i disable the VPN and allow "normal" internet connection, DynDNS is working fine
I'm not very good in this networking stuff, so: Is it even possible to have the NAS via VPN connected to the internet and still access it using DynDNS?
To me, it seems like it somehow should work: The DynDNS resolves to my local IP, the Ports are open and the NAS internal IP doesn't change when using this VPN. Looks like it should possible to get via public IP to my Router through the open ports to the connected NAS using it's internal IP.
But it doesn't work.
In order to access it using DynDNS, i have to disable the VPN.
Can someone explain what i got wrong - or why it's not possible to have both at the same time?
Oh, well, i got it working now! The NAS network settings provide an option to use "Multiple Gateways", i activated that - and now it's working.
But i don't really know why, so... is an user-fiendly explanation possible for this?