FRITZ!Box 3390 Serwis - Baza wiedzy

FRITZ!Box 3390 Serwis

Shared files and printers on a computer are not available over the Internet

You cannot access shared files and printers on a computer over your FRITZ!Box's Internet connection. Other connections using the SMB or CIFS protocol also cannot be established over the FRITZ!Box's Internet connection, for example connections to Strato HiDrive. Connections from the Internet to the home network that use the SMB or CIFS protocol are also not possible.


  • For security reasons, in the factory settings the FRITZ!Box blocks all access over the Internet to the TCP and UDP ports 139 and 445 ("NetBIOS Filter") that are used for file and printer sharing.

Important:Some of the settings described here are only displayed if the advanced view is enabled in the user interface. The configuration procedure and notes on functions given in this guide refer to the latest FRITZ!OS

1 Configuring the application to access the Internet without NetBIOS

  • Configure the applications so that they use secure transfer protocols such as VPN, HTTPS, or SFTP to access remote computers.

    Note:Refer to the manufacturer for information on using the application without the SMB/CIFS protocol and the necessary settings, for example consult the manual.


If you cannot or do not want to change the configuration of the application, disable the NetBIOS filter in the FRITZ!Box:

Important:When the NetBIOS filter is disabled, computers in the home network may be subject to more frequent attacks from the Internet. Therefore, set up a firewall on all computers in the home network.

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "Filters" in the "Internet" menu.
  3. Click on the "Lists" tab.
  4. Disable the option "NetBIOS filter enabled".
  5. Click "Apply" to save the settings.

Now you can use applications that must exchange NetBIOS packages with the Internet. This means that you can also access shared files and printers on remote computers over the FRITZ!Box's Internet connection.