On Linux, Once use kubevpn connect to k8s cluster network, then lost connection to internet network?

Reason

There is no optimal method for setting up DNS in the Linux system, as there are numerous types of Linux distributions with different network management configurations.

Expect

Set up a separate DNS for the tun device while preserving your internet connection.

Quick Recovery

If you've already lost internet connectivity after disconnecting, try these steps first:

1. Disconnect all KubeVPN connections

kubevpn disconnect --all

2. Check and restore your DNS configuration

Check your current /etc/resolv.conf:

cat /etc/resolv.conf

If it looks incorrect, you may need to restore it from backup or restart your network manager:

# For NetworkManager
sudo systemctl restart NetworkManager

# For systemd-networkd
sudo systemctl restart systemd-networkd

# Or reboot your system as a last resort

Resolve

Install and configure tools resolvectl to properly manage per-link DNS.

(1) Install tools resolvectl

Package information for resolvectl:

Operating system	Package name	Installation
AlmaLinux	systemd-resolved	dnf install systemd-resolved
Arch Linux	systemd	pacman -S systemd
Debian	systemd	apt install systemd
Fedora	systemd-resolved	dnf install systemd-resolved
Red Hat Enterprise Linux	systemd-resolved	dnf install systemd-resolved
Rocky Linux	systemd-resolved	dnf install systemd-resolved
Ubuntu	systemd	apt install systemd

(2) Verify install and enable service

Once installed, enable and start the service:

sudo systemctl enable systemd-resolved.service

sudo systemctl start systemd-resolved.service

Verify it's running:

resolvectl status

This shows information related to name resolution coming from the resolve daemon.

(3) Reboot

Please reboot your computer, this is important to ensure the changes take effect properly.

After rebooting, use kubevpn connect — everything should work fine and you'll maintain internet connectivity while connected to the cluster.

Diagnostics

If you still have issues after following the above steps, collect this information before opening an issue:

1. KubeVPN logs:

   kubevpn logs

2. Current DNS configuration:

   cat /etc/resolv.conf
   resolvectl status

3. Network interfaces:

   ip addr show
   ip route show

4. Your Linux distribution and version:

   lsb_release -a
   # or
   cat /etc/os-release