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Guest Access Disabled By Default In Windows 10 for SMB2 protocol

Jordan Ostreff

• 1 min read
Guest Access Disabled By Default In Windows 10 for SMB2 protocol

In Windows 10 after version 1709, Windows Server also after version 1709, the SMB2 client no longer allows the following actions:

  • Guest account access to a remote server
  • Fallback to the Guest account after invalid credentials are provided

SMBv2 has the following behavior in these versions of Windows:

  • Windows 10 Enterprise and Windows 10 Education no longer allow a user to connect to a remote share by using guest credentials by default, even if the remote server requests guest credentials.
  • Windows Server 2016 Datacenter and Standard edition no longer allow a user to connect to a remote share by using guest credentials by default, even if the remote server requests guest credentials.
  • Windows 10 Home and Professional editions are unchanged from their previous default behavior.

Solution 1

Re-Enable the guest account fallback - Microsoft are updating his manual periodically. In general idea is

  1. Go into Local Group Policy Editor
  2. Navigate into Administrative Templates - Network - Lanman Workstation.
  3. Then the Setting : Enable insecure guest logons has to be set to "Enable".
  4. Enable : Allow guest usage and solve the problem
  5. Disable : Will not allow guest usage and provide this problem.
enable insecure guest logons

Solution 2

Change the Samba "map to guest" parameter into configuration file ( smb.conf or smb4.conf ). Standard setting by default is "map to guest = bad user". This setting sets a guest session flag during initial SMB tree connect, and the listed Windows versions can end up failing to establish a session.

When changed to "map to guest = Never", then instead of silently dropping the connection, the Windows client prompts for a password.

  • reload Samba : service smb restart