I've installed armbian 5.38 debian stretch 4.14.14 on my Orange Pi PC .. after changing notwork settings (by using "armbian-config") from DHCP to Static , then back to DHCP, eth0 is not able anymore to get IP address..

 

"newtorkclt" return:

 

IDX    LINK             TYPE                 OPERATIONAL         SETUP

1        lo                 loopback           n/a                           unmanaged

2       eth0              ether                  n/a                          unmanaged

 

every suggestion will be usefull..

 

 

 

If a tool does not work properly, you need to edit it manually:

 

https://help.ubuntu.com/lts/serverguide/network-configuration.html

https://www.google.com/search?q=set+network+address+linux

 

... armbian-config will be examined and fixed.

/etc/network/interfaces file is correct but my Pi still not able to receive IP address from DHCP server...

I found this  https://medium.com/@cpt_midnight/static-ip-in-debian-9-stretch-acb4e5cb7dc1

 

by run the ifup eth0 command everything get fine

Remove /etc/network/interfaces and network-manager should pick up the address. And reboot in between.