Windows 8 Consumer Preview: Cannot acces NetApp CIFS share

Windows 8 Logo

If you try to connect to a NetApp CIFS share via Windows 8 beta you may cannot access the share because of the following error:

SMB connections fail with error “Invalid Signature”

Cause:

This behavior may be due to the “Secure Negotiate” feature added to SMB 2.24 for the Windows “8” beta release, which relies on the correct signing of error responses by all SMB 2 servers (including those supporting only protocol versions 2.0 and 2.1). Some third-party file servers do not respond with a signed error response causing the connection to fail.

Microsoft has two workrounds for this problem:

  • Enable signing on the third-party file server.
  • Disable “Secure Negotiate” on the client.

You can disable “Secure Negotiate” with the following PowerShell command:

Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters" RequireSecureNegotiate -Value 0 -Force

Checkout the Microsoft KB2686098

Update

Only some minutes after I released this blog post I got an anwser from Glenn Sizemore (NetApp) how you can enable SMB 2 signing on the NetApp.

ONTAP CLI:

options cifs.smb2.signing.required on

PowerShell:

ipmo DataONTAP
Connect-NaController controller
Set-NaOption cifs.smb2.signing.required off

Thanks for that.