Hello. I’m trying to enable two wired network adapters at the same time. The UI suggests it is possible by showing a separate on/off slider for each but when I toggle one on, the other toggles off. I am unable to turn both on at the same time. I note that clicking on the cog wheel and then the IPv4 tab seems to let me make changes but what I apply then seems to apply to both interfaces which is not what I would expect. Is there some sort of virtual interface that is assuming I only want one and don’t care which physical adapter I’m using?
Relevant System Information:
Framework Laptop 13 (Intel Ultra) with Ethernet expansion card inserted (USB Ethernet) and an OWC Thunderbolt Pro Dock connected via Thunderbolt 3 (PCI Ethernet)
I’ve tried to manually config and leave the gateway out of one but because they seem to be linked somehow, it doesn’t work. I have tried searching for solutions online but everything requires that you know which networking scheme your system is using (I don’t) and mucking about in various different /etc files which seems like it shouldn’t have to be the case given the UI controls available.
Does this only happen when using the GNOME settings UI, or does it also happen when enabling the connections with nmcli?
Does at least one of these two connections have the following setting enabled: IPv4 settings > “Routes…”, “Use this connection only for resources on its network”?
(* To be clear: leave that disabled for your Internet connection, but consider enabling it for connections that are local-only or otherwise not for internet access.)
I haven’t tried nmcli. On Desktop I try to stick with the herd in the GUI for things that seem to swerve all over the place from one version to the next (like networking configuration schemes seem to). Is Ubuntu Desktop 25.04 relying on Network Manager? The official Ubuntu Server docs say “Network configuration on Ubuntu is handled through Netplan” and the Desktop docs don’t say much on the topic and don’t delve into any command line or config file stuff. I assume they are the same or similar but on Desktop the GUI seems to be where you get sent by the docs.
I did see that and had an “Ah! That must be the way!” moment before toggling that in the USB Ethernet (secondary adapter for a local-only network) settings and then losing my internet connectivity provided by my PCI Ethernet (main network with my internet router). That was when I first realized that every time I was changing settings in one, it would change them in both.
So I feel like the UI is hiding some interface abstraction layer from me. It is treating all wired interfaces as one somewhere under the hood and yet presenting them as separate with their own toggles and config gear icons. If it shows independent on/off toggles, it should allow independent on/off. Different settings buttons, different settings. Either the GUI needs a redesign that makes it clear that you can’t do this (a radio button to choose one out of a list if interfaces to enable and a single gear icon for the currently selected “Wired Network”), or it should support what it seems designed to.
Anyway, thanks for your help. I will dig a bit deeper into using nmcli for this but I do feel like it needs a bug report and/or feature request too.
STATE CONNECTIVITY WIFI-HW WIFI WWAN-HW WWAN METERED
connected full enabled disabled missing enabled no (guessed)
So that seemed legit but the single enabled WWAN seemed to suggest that I was on the right track with my feeling that “it is treating all wired interfaces as one somewhere under the hood.” Then I found this Using NetworkManager (NMCLI) on Ubuntu and Debian and specifically the existence of nm-connection-editor and now I have the vocabulary for this. I had one network connection with two devices assigned to it.
I am now playing with that tool and have created a new Ethernet connection, assigned it the 10GbE PCI device, and edited the other one to only have the USB 2.5Gb device. Testing continues but I think I’m on a good path now. Thanks again. I will report back when I have it sorted out.
So the missing piece of the puzzle for me on Ubuntu Desktop was the nm-connection-editor utility. With some trial and error there making new connections, editing and ultimately deleting the one that had both devices in it, I was able to get to a spot where each was able to be enabled, disabled, and configured independently in the GNOME Settings → Network GUI.
Remaining things to sort out are:
Having the connection names I set show up in the Settings and Desktop UI instead of “PCI Ethernet” and “USB Ethernet” which must be hard coded/configured somewhere; and,
Setting up multiple addresses/networks on the same connection without VLANs (similar to the old and now deprecated IP-aliasing) so I can reach devices with default IP addresses on different subnets when setting them up.
I note also the plus icons in the Settings → Network GUI and those seem to be tied to those “PCI Ethernet” and “USB Ethernet” headings. Clicking them offers to create a new “Profile”. I guess understanding Profiles is #3 on my list above.
