mzinz :
You have provided no helpful detail here.
How many devices are you connecting onto the network?
What are they connecting to? A router?
Does the router connect up to a modem? What type of service?
What happens when you connect the devices?
The details you're asking for do not solve the issue of the Ethernet port not working, just solves a network standpoint of the issue. If you insist, I am in a work lab, I use ONE connection which leads back to our switch, that uses a static connection. I have available IPs to use, and have properly programmed a test hard drive with the set of drivers needed to work with these units as well as the proper network information needed.
This is not to test wireless connectivity, since they connect just fine, this is for a hardwired connection, in which... pc to pc works, and a connection to a internet networking does not (via Ethernet).
From the connection type - Switch to PC = no internet, meaning no solid green light, no blinking yellow light off the Ethernet port
From the connection type - PC to PC = Connectivity between the two, meaning solid green, blinking yellow lights off the Ethernet port
I am not trying to transfer data or files (cross over cable) between the PC to PC connection
I am trying to understand why the Ethernet port is working... if you'd like to use the term Ad-Hoc... but will not work from switch to PC (internet connection)