NAS 542 DNS Disconnect/Connect Problem

FloG93

Hi there! 
I got a problem with my 542 NAS. It's super strange to me and I registered here in this forum because I'm out of ideas.
Main problem was that my 542 NAS had no internet connection whatsoever. Every other device, let it be wlan or lan, had an inet connection. Simply the NAS don't.
" Okay then open the needed ports for communication" 
I did! 20/21/443/5000/5001/80...all of them.
Nothing happened.
Okay I thought to my self.. let's see how far the ping goes. 
I can ping my router with the internal ping tester just fine. Over ssh no problem aswell. 4 out, 4 in, 0 package loss! 
But!! If I try pinging outside my home network (e.g. 8.8.8.8) I get an error.
NOW comes the strange part which confuses me a lot.
When I'm changing the default primary dns of the NAS to e.g. 8.8.8.8 nothing changes ... If I then enter a secondary dns e.g. 1.1.1.1 the NAS has an connection!!! It works...
BUT! only for a couple of seconds. It lastet the longest with almost a minute. Then the connection cuts down.
If I then go back to the NAS dns settings and change NOTHING AT ALL just hit the apply button a let the waiting wheel spin...the NAS has a connection again for again a short period of time (max. 56 sec.).
I need help please! 
Information for my system:
Fritzbox 6490 192.178.168.1 dhcp
NAS static IP given from Fritzbox with 192.178.168.26

Thank you in advance !

Gz flo

Mijzelf

That doesn't sound like a dns problem. More a gateway problem. Are you sure you specified the right gateway? That should be your router.

Batou

You should try ping the DNS on your router to check if it's working.
Like @Mijzelf said, maybe there is mis-config of gateway setting.