nominatim Installation, clients require internet connection?

Nominatim is not a map server but a geocoding server. The map you see always comes from the server - unless you install a tile server too!

thanks a lot for the quick answer, honestly I wondered where the image rendering takes place in nominatim 🙂

I try to get your wording straight so you can communicate more effectively in the OSM ecosystem in the future. Please ignore this post if it sounds too pedantic.

funksen wrote:

imported the OSM maps from Austria,

You imported OSM data (or "an OSM dump"), not "maps". Maps are images of something. You didn't import an image to your database ;-)

funksen wrote:

everything works perfectly and super fast, but then I tried other countries I hadn't imported, and still it works?

There may be confusion on what exactly "works", and how.

What you mean (probably) is that you both can view a map and can geocode addresses.

funksen wrote:

I shut down my client pc internet connection, and nothing worked, not even the imported map from austria, just grey squares

"nothing works" may be a misunderstanding: you do not see a map, because map tiles are not accessible, because you have no internet connection. But the geocoding part of nominatim should still work.