Hi,
My name is Jaspreet and I work for the Social Media and Community Team at Dell. You can install the Ethernet controller driver from the Drivers and utilities disc that came along with the computer.
If you do not have the disc then follows the mentioned link for Ins N4030:
http://tinyurl.com/6qn48bs
or
http://tinyurl.com/7mv99lf
Please revert back in case you need any clarifications.
Thanks,
Dell-Jaspreet K