SUMMARY *** This is a problem you won't see if you only use wifi, however if you use ethernet via the RJ45 connector then maybe you will have this problem. If you plug into a network using an ethernet wired connection (with WIFI disabled) and have DHCP setup in the plasma network configuration. When the system obtains it's IP address it fails to setup the default gateway so no internet access is available. If you type route add default gw 192.168.0.1 enp2s0 then everything then works. How come the gateway is no longer setup in the routing table automatically when hot plugging an ethernet cable? WIFI works fine. routing table after ethernet cable plugged in. route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface link-local 0.0.0.0 255.255.0.0 U 1000 0 0 virbr0 192.168.1.0 0.0.0.0 255.255.255.0 U 100 0 0 enp2s0 192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0 Below is the routing table for WIFI showing the extra line starting with 'default' route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface default _gateway 0.0.0.0 UG 600 0 0 wlp3s0 link-local 0.0.0.0 255.255.0.0 U 1000 0 0 virbr0 192.168.1.0 0.0.0.0 255.255.255.0 U 600 0 0 wlp3s0 192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0 *** STEPS TO REPRODUCE 100% reproducible on my laptop OBSERVED RESULT No default gateway setup in routing table EXPECTED RESULT default route should be added when ethernet cable used. SOFTWARE/OS VERSIONS Operating System: KDE neon 5.23 KDE Plasma Version: 5.23.4 KDE Frameworks Version: 5.89.0 Qt Version: 5.15.3 Kernel Version: 5.11.0-43-generic (64-bit) Graphics Platform: X11 Processors: 8 × Intel® Core™ i7-2670QM CPU @ 2.20GHz Memory: 15.6 GiB of RAM Graphics Processor: GeForce GTX 570M/PCIe/SSE2 ADDITIONAL INFORMATION
Created attachment 144793 [details] No default route If you have "Use only for resources on this connection" then the default route for that connection won't get setup and you won't have internet access. Untick if this connection is your route to the internet. The message could may be a bit clearer in regards to disabling the default route and it's consequence.
See above comment and attachment. Closing. Not a bug.