Sure you’re right. But strengthening the setup is something of later concern (the minimum would be that only my own ip woild be allowed, but setting up VPN is also an option).
But that does not fix this problem. I should be able to manage it over the WAN interface, speicially now its on the LAN. I’m wondering if the device is broken or not and how I could verify such…
Edit: it appears that I’m suffering from this problem: http://forum.mikrotik.com/t/hap-ac-faulty-seriers-very-poor-lan-performance-switch-problem/96655/1
Cooling the unit down in the fridge turns it into a working wan interface again. The question is: for how long? And what can I do to sustain it?