What is an ip ban e.g. In Minecraft?

Is an IP ban if the router is banned or the PC

No your IP will then be banned as the name suggests

The IP you represent to the outside is banned. Not the local IP of your computer.

Your public IP address - i.e. The one that points to your router - is banned. Not your local address from the computer. This means that no one in your network can connect to the corresponding server.

At a LAN party, your PC is banned because you usually gamble within a local network and each PC there has its own IP address.

However, if you play on the Internet on public servers, the entire router will be blocked / banned with the IP ban.

The IP address can usually be changed with a DSL connection by restarting the router.

An IP ban means that the IP of your network is banned. Since all devices in your home are in the same network and go through the same router, access from all these devices would no longer be possible.

At least until you get a new IP. Happens once a day with most internet providers or even when you restart your router.

Is it so at Unitymedia?

Can I also change the IP with a VPN?

Usually with all providers

Even simpler - unplug the router and plug it in again. You will usually get a new IP. Otherwise yes - VPN helps too!