Check SMB Versions in Windows


  • SMB3 is the default protocol for sharing files in OS X El Capitan. SMB3 helps protect against tampering and eavesdropping by encrypting and signing data “in flight.”

  • Encryption. SMB3 provides end-to-end encryption to protect data and secure
    communication on untrusted networks. SMB3 in El Capitan uses AES-CCM for encryption to ensure communications between client and server are private.

  • Signing. To guard against tampering, SMB3 adds a signature to every packet transmitted over the wire. SMB3 uses AES-CMAC to validate the integrity of the signature, ensuring the packets have not been intercepted, changed, or replayed
    and that communication between hosts is authenticated and authorized.

  • Power. Encryption and signing of SMB3 connections are fast and power efficient. Both AES-CCM for encryption and AES-CMAC for signing are dramatically accelerated on modern Intel CPUs with AES instruction support.

  • Authentication. SMB supports Extended Authentication Security using Kerberos and NTLMv2.

  • Efficient. SMB features Resource Compounding, allowing multiple requests to be sent in a single request. In addition, SMB can use large reads and writes to make better use of faster networks as well as large MTU support for blazing speeds on 10 Gigabit Ethernet. It aggressively caches file and folder properties and uses opportunistic locking to enable better caching of data. It’s even more reliable, thanks to the ability to transparently
    reconnect to servers in the event of a temporary disconnect.

  • Transparent reconnect. El Capitan supports Persistent Handles for transparent failover and reconnects to enterprise SMB3 file servers.

  • Compatible. SMB is automatically used to share files between two Mac computers running OS X El Capitan, or when a Windows client running Windows 8 connects to your Mac. OS X El Capitan maintains support for AFP SMB2 and SMB network filesharing protocols, automatically selecting the appropriate protocol as needed.

Windows and SMB...

  • SMB 1 - Windows 2000
  • SMB 2 - Windows Server 2008 and Windows Vista SP1
  • SMB 2.1 - Windows Server 2008 R2 and Windows 7
  • SMB 3.0 - Windows Server 2012 and Windows 8

Launch Powershell as administrator and type Get-SmbConnection. Sample output:

ServerName    ShareName UserName    Credential    Dialect NumOpens
----------    --------- --------    ----------    ------- --------  IPC$      Win10\tester Win10\tester 3.0     1   IPC$      Win10\tester Win10\tester 2.0.2   0

Link to OS X El Capitan Technologies Overview.

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