Have had a problem with new Raspberry Pi 4 to connect to a network after reboot.
Route -n
shows nothing, no gateway, nothing
Message over the network connection icon in the menu bar says "eth0 Link is up, configuring" and never do the connection to my network.
sudo ip link ls eth0 -shows card is enabled
I was thinking my card is broken but I've solved this issue by added line of code
iface eth0 inet dhcp
to
/etc/network/interfaces
then
sudo ifdown eth0
and
sudo ifup eth0
This wake up my ethernet card to get connection to my network but did't fix the problem so far.
after next reboot I've had no connection.
I've commented that line what added to /etc/network/interfaces and rebooted my RPI
and now eth0 has established the connection to the network.
Is is so weird !I don't know what is wrong yet but its working for me for now.