Second wired connection showing up with only one physical network connection

[sandro4912]

I have something strange going on here.

My Computer has one Wifi Card and one Network card.

In Manjaro however it always shows me two Network cards:

 sandro@sandro-pc  /  ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether ac:22:0b:78:b5:f3 brd ff:ff:ff:ff:ff:ff
3: wlp6s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DORMANT group default qlen 1000
    link/ether e0:d4:e8:79:62:97 brd ff:ff:ff:ff:ff:ff
4: enp0s20u2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether 00:1e:10:1f:00:00 brd ff:ff:ff:ff:ff:ff
 sandro@sandro-pc  /  nmcli connection show
NAME                UUID                                  TYPE      DEVICE    
HUAWEI_BBF0         a7fb4035-5f70-4f1f-96e5-8d3e7a3e12c9  wifi      wlp6s0    
Wired connection 1  51ed38e7-ef27-37dc-b084-9e46749bf67d  ethernet  enp0s20u2 

As you can see my wired connection is enp0s20u2.

After every restart Manjaro connects to enp0s20u2. The weired thing is my Network connection is not working with that connection. I have to set it every time manually to enp3s0 which is not even showing up in the physical connections.

Is there something strange mapped in the system? Any idea why I need to switch?

I think this behavior only showed up after some system update.

[bogdancovaciu]

Manually remove both enp3s... connections from network manager settings, and manually add a new wired connection and assign it to your LAN card.

[sandro4912]

Were do I find it. Is it in NetworkManager.conf ?

[sandro4912]

In the settings is like this:

As you can see. In the connections only enp0s20u2 shows up. In the availabe Networks also enp3s0

[bogdancovaciu]

They are both connected. Make sure is not set to Restrict to device for both on the same. In General you can set what connection to happen automatically, and as said, you can remove both and manually ad one.

[sandro4912]

yes but I wonder why It even shows up two? I have only one network card with one ethernet port on the machine.

[bogdancovaciu]

@sandro4912

I wonder why It even shows up two?

Check if you have also dhcpcd service enabled … that might cause the duplicate and generate a new config for the same device, hence NetworkManager service fails

[sandro4912]

I deleted all the connections and network manager and added the ethernet again. now it works