Kubuntu 25.10, plasma 6.4.5
I’ve imported a wireguard config file from several VPN providers using both the networkmanager and have tried nmcli command line. It appears they connect, but there’s no internet access. I’ve looked at the basic settings and don’t see anything obvious but also I’m a bit lost what to do next. This also seems to be a common challenge.
Ideas on how to debug?
So, update. It’s connecting, but upload speed is extremely slow. Less than 1Mb/s. I don’t think it’s the VPN server, it does the same from 2 VPN providers and multiple servers. And when I use the same server via the VPN’s GUI, it works fine.
I’ve confirmed now with 3 VPN providers, multiple wireguard config files, and multiple servers. If I manually import any of the VPN providers wireguard config files, I’m limited to exactly 0.41Mb/s upload speed. But using the GUI from any of those providers gets me the expected upload speeds (40-100Mb/s).
Any ideas or help appreciated.
Fixed.
Manually setting MTU to 1280 or 1400 seems to have fixed the upload problems.