Ubuntu: Missing network interface and no UI

Question

I'm running 14.04.5 and somehow my system got into a state where my nVidia drivers, lightdm, and all window managers seemed to contribute to a broken graphical system. So, I uninstalled all of it while keeping the base system. I can now boot to a prompt.

However, I don't have a valid wired network interface any more.

I attempted to add my bootable USB drive as an Apt repository and updated, except nothing seemed to be findable/installable. So, I took it back out. This to say that I don't currently have a way to install any packages.

I see that the e1000e kernel module is loaded, so my network interface should be accessible. I tried deleting /etc/udev/rules.d/70-persistent-net.rules (implied that it might work here: https://serverfault.com/a/623973/93185) and then rebooting, but nothing changed.

I'd appreciate some insight. Thanks.

Solution

To show all physical interfaces (in any state):

ip link show

To specifically show eth0:

ip link show eth0

This might show:

2: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000
    link/ether 3c:97:0e:bb:8e:a8 brd ff:ff:ff:ff:ff:ff

Note that it's down.

To configure the interface for DHCP and bring it up:

dhclient eth0
ip link set eth0 up

Comments

[acejavelin]

No offense, but it sounds messed up pretty bad so at this point why bother? Just backup your home directory and reinstall Ubuntu 16.04 LTS, then restore your home directory.

[Dustin Oprea]

It's not that far gone, but I do require 14.04 . The system currently boots cleanly and I merely need to fix my network connectivity. There are just a couple of commands that I'm unfamiliar with I'd require in order to do this.

[acejavelin]

So you only need the command line, no GUI? Sorry, I missed that part. Otherwise, for the amount of work involved in restoring anything, you could just reinstall 14.04.5 and reinstall your software (your settings and documents would be in your home directory) and it would probably be quicker.

[Dustin Oprea]

Yes, but I have corporate security stuff configured that I require to connect to the office. I can't expect that I'll sufficiently be able to find all of it and likely won't be able to get it re-integrated correctly on the other side.

[acejavelin]

Understood... Can you append the output of nmcli dev show eth0 to your original question? (I am assuming eth0 is your network device, adjust as needed)

[Dustin Oprea]

Doesn't exist. command-not-found shows that it's park of network-manager, which must've got uninstalled (it must've been considered graphical, which seems reasonable).