No ethernet connection in Ubuntu 19.04 after changing motherboard

so I've recently built a new PC and kept my SSD/HDD, so everything except my disk drive which has ubuntu installed on it changed. The ethernet connection doesn't work (it used to work on old PC on same ubuntu install), Wi-Fi still works through an USB adapter. Ethernet Connection works on another drive with Windows install so I know the port is working fine, it's only on Ubuntu. I'm looking for a way to get ethernet working without reinstalling ubuntu

my ifconfig:

r0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 inet6 fe80::3c60:9eff:fe5b:8d94 prefixlen 64 scopeid 0x20<link> ether 3e:60:9e:5b:8d:94 txqueuelen 1000 (Ethernet) RX packets 40313 bytes 5565185 (5.5 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 1515 bytes 472236 (472.2 KB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 78701 bytes 6556181 (6.5 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 78701 bytes 6556181 (6.5 MB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255 ether 52:54:00:71:a9:c1 txqueuelen 1000 (Ethernet) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
wlx0024010c2ae6: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.1.41 netmask 255.255.255.0 broadcast 192.168.1.255 inet6 fe80::bf4c:1503:726:f000 prefixlen 64 scopeid 0x20<link> ether 00:24:01:0c:2a:e6 txqueuelen 1000 (Ethernet) RX packets 73240 bytes 82584023 (82.5 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 51703 bytes 7315654 (7.3 MB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

as you can see there's no eth0 or eth1 in ifconfig, maybe that has something to do with the problem?

my /etc/NetworkManager/NetworkManager.conf:

[main]
plugins=ifupdown,keyfile
[ifupdown]
managed=false
[device]
wifi.scan-rand-mac-address=no

"sudo lshw -C network" output:

 *-network DISABLED description: Ethernet interface product: Ethernet Connection (7) I219-V vendor: Intel Corporation physical id: 1f.6 bus info: pci@0000:00:1f.6 logical name: eno1 version: 10 serial: 04:d4:c4:47:ce:15 capacity: 1Gbit/s width: 32 bits clock: 33MHz capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=3.2.6-k firmware=0.5-4 latency=0 link=no multicast=yes port=twisted pair resources: irq:126 memory:a5200000-a521ffff *-network:0 description: Ethernet interface physical id: 2 logical name: br0 serial: 3e:60:9e:5b:8d:94 capabilities: ethernet physical configuration: broadcast=yes driver=bridge driverversion=2.3 firmware=N/A link=no multicast=yes *-network:1 description: Ethernet interface physical id: 3 logical name: virbr0 serial: 52:54:00:71:a9:c1 capabilities: ethernet physical configuration: broadcast=yes driver=bridge driverversion=2.3 firmware=N/A ip=192.168.122.1 link=no multicast=yes *-network:2 description: Wireless interface physical id: 4 bus info: usb@3:13.4 logical name: wlx0024010c2ae6 serial: c6:35:71:76:9b:db capabilities: ethernet physical wireless configuration: broadcast=yes driver=rt73usb driverversion=5.0.0-25-generic firmware=1.7 link=no multicast=yes wireless=IEEE 802.11 *-network:3 DISABLED description: Ethernet interface physical id: 5 logical name: virbr0-nic serial: 52:54:00:71:a9:c1 size: 10Mbit/s capabilities: ethernet physical configuration: autonegotiation=off broadcast=yes driver=tun driverversion=1.6 duplex=full link=no multicast=yes port=twisted pair speed=10Mbit/s

"cat /etc/network/interfaces" output:

# ifupdown has been replaced by netplan(5) on this system. See
# /etc/netplan for current configuration.
# To re-enable ifupdown on this system, you can run:
# sudo apt install ifupdown

"cat /etc/netplan/.yaml" output

# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network: version: 2 renderer: networkd ethernets: enp0s31f6: dhcp4: yes bridges: br0: dhcp4: yes interfaces: - enp0s31f6

also, it says 'Ethernet Network device not managed' when I click on the network icon on top right

SPECS:

ASUS Maximus XI Hero (No Wi-Fi)
Intel Core i9 9900k @ 3.6Ghz
MSI GEFORCE RTX 2080 Ti
32GB DDR4 Ram @ 2666MHz

1 Answer

In your /etc/netplan/01-netcfg.yaml file, please change both instances of enp0s31f6 to read eno1, the new logical name of your ethernet. Follow with:

sudo netplan generate
sudo netplan apply

Your ethernet should now be working correctly. If not, try a reboot.