@PaoloHolzl Something more.

Guest Permissions now are
Control the data that guests can access.
DISABLED Allow guests to see each other
DISABLED Allow guests to access your local network

  @PaoloHolzl 

Hi, thanks for posting here.

If failing to log into the web interface of the router, you may refer to this thread.

Sorry that I am confused about you mentioned"The problem is that user connected as Guest can enter to shared directory of the main network, and this in guest mode have to be not allowed."

  @Marvin_S  Maybe I was expecting something that this router can't do.

Upstream of this router I have a switch to which a file server is connected.

I expected that by choosing 'DISABLED Allow guests to access your local network' I would be able to prevent the visibility of this file server and I would be able to allow Guest users connected to the access point to only go out to the Internet.

Correct me if I'm wrong, this is probably only possible if the file server is directly connected to the router ports and not upstream.

  @PaoloHolzl 

Hi, thanks for your update.

Please refer to the guide to know more about  differences between Access Point mode and wireless router mode.

Under the AP mode, the Guest Network will not be separate from the main network. Clients connected to the guest network can access to the main network.

So that is the reason why you can still access to the main network on Archer AX53 when your device is connected to the guest network. 

You may use wireless router mode instead.