If I am using private namersevers, how come this website can tell me the real ones?

I thought private nameservers were so no one knew what nameservers you were actually using.

When I do a whois it returns my private nameservers.

correctly identifies the nameservers that I am using, not my private ones.

Anyone can look up the nameservers that a domain points to. The trick to being totally hidden is to buy a random BS domain like whateverlolzwebserver.com, and do the whois privacy on it. Never put up a website on that domain and create new "private" nameservers based on that domain. Even though the name of your nameservers can be seen, the whois info is hidden and there’s no other info about that domain online.

Hosting companies do this same trick so their clients can have unbranded reseller accounts.

I have domains with private reg and private nameservers. When I do a whois on it I get private whois info and the "private" nameservers based on that domain (NS1.domain.com). That’s what I would expect people to see.

But that website I listed above shows the real nameservers.

You’re probably using ‘vanity’ nameservers rather than true private nameservers. The true nameservers are just found by inspecting the zone file more than likely.

What’s the difference? What’s a zone file?

I created the nameservers in Godaddy by following a tutorial. Is that a vanity nameserver?

I’ve found this website often gives the wrong location and sometimes IP of the website you look up:

Are they just trolling? For example, they say Google.com is hosted in Germany.