Ok, after another couple of hours of breaking my head over this I finally found the culprit. The NAS was still set to use the VPN when using the internet, removing this rule from the VPN routing rules solved it. As always the answer was hiding in plain sight.
Thank you all for your support!
@RMerlin The Synology blocks an IP after 3 false attempts, however if I toggle the upnp feature in the asus I can login normally in the short time period after that, so that does not seem to be the problem. By disabling the upnp support I assume you are referring to the automatic router settings...
We might be on to something,
As you can see in my earlier post the MAC for the NAS is 00:11:32:xxxxxxx
Now because of the wiring here in my building the router is in a central location and than the wall socket (LAN 1) has a unmanaged switch connected to it that has the NAS and a long cable to...
@octopus Removing the "local port" doesnt fix the issue. It still only works after toggling the upnp functionality.
@mattiL Going through the Synology it did not want to connect/find the router, so I ended up changing the settings manually
I have been struggling the last couple of days to get port forwarding to work with the Merlin firmware on the Asus RT-AC68U. I am trying to access the Synology NAS from the outside network and I can only get the router to forward ports for a very short period of time.
I have narrowed the problem...