Thanks for the investigation work, I emailed the Ubuntu devel list about changing the default, let's see how the discussion goes https://lists.ubuntu.com/archives/ubuntu-devel/2019-February/040588.html
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to network-manager in Ubuntu. https://bugs.launchpad.net/bugs/1814262 Title: Wired interface gets impossibly high metric 20100 Status in network-manager package in Ubuntu: New Bug description: Actually this might be a heisenbug. I've had an issue with this all morning since network-manager got an update this morning, but just now *while this bug was being submitted* it decided to correct itself. What I was getting was, on a machine (Dell XPS 13 9370) with WiFi and a (Caldigit) Thunderbolt 3 dock with an ethernet port: After the network-manager update I noticed everything was slower than I was used to, and in gnome-shell the network icon showing was the WiFi one, not the wired one. Looking at the output of route, or route -n for simplicity, I would see this: rachel@rainbow:~$ route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.1.254 0.0.0.0 UG 600 0 0 wlp2s0 0.0.0.0 192.168.1.254 0.0.0.0 UG 20100 0 0 enp63s0 169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 wlp2s0 192.168.1.0 0.0.0.0 255.255.255.0 U 100 0 0 enp63s0 192.168.1.0 0.0.0.0 255.255.255.0 U 600 0 0 wlp2s0 So the metric on the default route on enp63s0 had 20,000 mysteriously added to it, which would obviously make it extremely low-priority. The system was choosing the wifi connection instead, which isn't that great in my office, hence observable slowness. Now, this morning, this seemed to be the sticky situation. It didn't show any sign of changing, whatever I did, after restarts of network- manager, undock/redock, reboots, etc. I could change it manually with ifmetric (and it would work), but that was about it. I would have reported the bug then, but I had to go out. When I got back I plugged in and initially saw the same thing again (that's where the above snippet was pasted from). But *while* the ubuntu-bug network-manager command was running, I noticed the gnome-shell network icon switch to wired, checked again, and saw: rachel@rainbow:~$ route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.1.254 0.0.0.0 UG 100 0 0 enp63s0 0.0.0.0 192.168.1.254 0.0.0.0 UG 20600 0 0 wlp2s0 169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 wlp2s0 192.168.1.0 0.0.0.0 255.255.255.0 U 100 0 0 enp63s0 192.168.1.0 0.0.0.0 255.255.255.0 U 600 0 0 wlp2s0 So now the wifi connection has 20,000 added to it, which may still be wrong? But I wouldn't otherwise have noticed it because the system is again *behaving* as expected. This all seemed to happen after the network-manager upgrade (from 1.12.6-0ubuntu4 to 1.15.2-0ubuntu1) this morning. I can't say if these metric+20,000 values were present before then, because I didn't have any cause to go looking at it, it always just worked. Could it be some issue with how the newer network-manager, or one of its associated packages, is figuring out the metrics on new connections? Like it's running some new heuristic to determine which one should really be the preferred? If it's like it was just now, when it fixed itself after a minute or so, that's not really a problem, but if it's like it was this morning when it just seemed to be stuck with the ethernet connection at 20100, it is. ProblemType: Bug DistroRelease: Ubuntu 19.04 Package: network-manager 1.15.2-0ubuntu1 ProcVersionSignature: Ubuntu 4.18.0-13.14-generic 4.18.17 Uname: Linux 4.18.0-13-generic x86_64 ApportVersion: 2.20.10-0ubuntu19 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Fri Feb 1 13:15:06 2019 IfupdownConfig: # interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback InstallationDate: Installed on 2018-09-11 (142 days ago) InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180214) IpRoute: default via 192.168.1.254 dev wlp2s0 proto dhcp metric 600 default via 192.168.1.254 dev enp63s0 proto dhcp metric 20100 169.254.0.0/16 dev wlp2s0 scope link metric 1000 192.168.1.0/24 dev enp63s0 proto kernel scope link src 192.168.1.106 metric 100 192.168.1.0/24 dev wlp2s0 proto kernel scope link src 192.168.1.101 metric 600 NetworkManager.state: [main] NetworkingEnabled=true WirelessEnabled=true WWANEnabled=true RfKill: 1: phy0: Wireless LAN Soft blocked: no Hard blocked: no SourcePackage: network-manager UpgradeStatus: Upgraded to disco on 2019-01-13 (18 days ago) nmcli-dev: DEVICE TYPE STATE IP4-CONNECTIVITY IP6-CONNECTIVITY DBUS-PATH CONNECTION CON-UUID CON-PATH wlp2s0 wifi connected full limited /org/freedesktop/NetworkManager/Devices/2 Strange Noises ae544444-3c3d-4714-8bf5-7e56bb7249c6 /org/freedesktop/NetworkManager/ActiveConnection/2 enp63s0 ethernet connected limited limited /org/freedesktop/NetworkManager/Devices/4 enp63s0 7d394ed8-72c6-4081-9dac-18e320acdafd /org/freedesktop/NetworkManager/ActiveConnection/3 lo loopback unmanaged unknown unknown /org/freedesktop/NetworkManager/Devices/1 -- -- -- nmcli-nm: RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN running 1.15.2 connected started full enabled enabled enabled enabled enabled To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1814262/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
