Urban Terror 4 Server configurations

I use to play Urban Terror from time to time with some friends, usually over the LAN when we meet somewhere. But we often have had some issues that stuff like Voting or the map-cycle did not work or meet our expectations, because of a wrong or no configuration of the server. Therefore I looked a bit into how to configure an UrT4 Server – and I will publish some of the main “Good-to-knows” here.