Small electronic device gets assigned 169.254.X

Hi,

I will try to explain this and keep it simple. I have a Boeing 737 homecockpit and i’m using these two small screens with a keyboard that use ethernet connection which is connected to my ethernet switch then that connects to my main PC for gaming.

My main PC uses intel built in WIFI (maximus XII Hero WIFI)

When i switch on my small screens to obtain the IP address it shows 169.254.X but this should show 192.168.X like i have for my wifi?

Does anyone know why my device is picking up 169.254?

Here is the manual to my small computer screen

https://www.cpflight.com/docs/prodot...O%20manual.pdf


I emailed the Company (Cpflight) they said

Hello, I do not know, I do not know your setup. For sure thje only thing that I can say you is that the CDU when start re-know the ethernet class and so syncronize to your ethernet class

so if your router have the address 192.168.1.1 the CDU will obtain an anddress like 192.168.1.xxx

If your router has a different class the CDU copy the firts 3 number and assign automatically like firth the firts free address. So if you now see 169.254.1.xxx mean that your router has this class. I do not know why,

Only you know the change that you have done to your LAN.

Hearsepilot said:

Can you access the device to see if DHCP is turned on on that device and turn it off if it is and see if its possible to change its IP number.

Hi, DHCP is enabled on. So with that 169.254 it still works on my software addon because i need that ip address to enter it so it can communicate. Just never seen that 169.254 before

I get this 169.254. .. address problem with my Apple TV, but rebooting the router and Apple TV will fix it... (Device can't find an address from the router! so defaults to 169.254. !!)

Hey

Their explanation saying that your router has a class of 169 is stupid. If that was the case, nothing would work.
As others have said, its because the CDU cannot find an address, so it defaults to 169.

Firstly, connecting the switch to the Computer isnt going to work. You need to connect the switch to the router. This will then assign the correct IP address.

Good luck

Edit:
You can connect the switch to the computer, but then you'd need to assign a static IP and gateway to the machine. I doubt the CDU has the abilty to create a static address, which in turn will always give an IP address conflict and wont work, so its 'Switch to Router'