Normally when you’re on a VPN all the network traffic to and from your device is going through the connection to the VPN server, e.g. browsing the internet, online games, etc. It can cause issues with other online services and uses bandwidth (cheap as it is) many VPS provider charges for.
A split tunnel tells the VPN client to only send certain traffic through the tunnel. My wireguard setup assigns IP addresses for the VPN interfaces in the subnet 192.168.2.x, so only traffic addressed to IPs on that subnet get sent through the tunnel. In wireguard it’s a single line in the config file:
AllowedIPs = 192.168.2.0/24
Netbooks need to come back with modern hardware.
If I need an ultra-portable computer one in a usable form factor would be amazing.