Mesa 7i96 no more reachable trough ethernet

Good evening guy's,

the last days I started my LinuxCNC PC and normaly a notification in the right top corner pops up that a ethernet connection is made. But this times not. I dont know if the problem was that I used a wifi stick and the network manager gets stuck or the ethernet of mesa board is broken.
I tried three days to get it working, did a lot of changes in the debian system on networking but getting it not working. Now is the point where I need help because I dont get it run

The mesa board is set to the fixed eprom address 10.10.10.10 trough the jumpers. I even buyed a network card (showed up as enp4s7) and there is my mesa board physically connected. I comment all the entrys I made before out "#" out in the /etc/network/interfaces file expect the auto lo. I can ping ethernet card which is set to 10.10.10.12 with no isssues but pinging the mesa card dont work with 10.10.10.10.

I dont where to start to get it run? Is there another why to communicate to the mesa board to check if ethernet is working correct? I also tried to ping from my windows pc configuring it to 10.10.10.12 but with same results in linux debian (using stretch). If I restart my linux pc the network manager dont starts automatically and all the configured connections trough the network manager are lost.

Do you can help me out here and have some ideas what I can check?



 

What does the command

ip a

report?

Hi PCW, thanks for your help.

Here is the result. Sry for the pictures I made, but for me is this the easiest way..

OK so no link

Does the 7I96 have its link light on? (Orange LED on RJ45)

Both leds on the rj45 connector are off. With and without connected cable.
Only the PWR led is on and with connecting the power 5v the user led shift vom right to left then stays off. 

If you get no link lights on the 7I96 with a known good PC Ethernet port/cable
That suggests the 7I96 ethernet section has failed

You might verify that the PC ethernet port works for other connections

Good morning PCW thanks for your advice this one was the right, I could identify the cable which was broken...I would never have believed
With the new cable bot leds on the 7i96 connector are on.

But now because I thought it was a network configuration problem the last days and changed so much nothing works.

At startup the network manager dont boots up..on the top right corner it says network manager is "deactivated" what have I to do it right to configuring everything?

EDIT: Now everything works fine. I had to enable the NetworkManager service trough terminal with systemctl enable NetworkManager than systemctl start NetworkManager. After that even after bootup the NetworkManager starts automatically.
Problem that the network manager sets the connection to DHCP not manual and also chooses the wrong network connection.

If i define static ip in the /etc/network/interfaces what I have to do that the network manager dont change or dont manage this connections which are defined in the file or leave this at it is without deleting the network manager?
 

If you manage a network connection via the interfaces file,
the network manager _should_ automatically leave that interface alone.