Glossary Storage Systems, Protocols, and ScaleSMB

SMB

SMB, Server Message Block, is the protocol Windows uses to share files and folders over a network. Most NAS systems support it, so Windows and Mac users can open shared folders as network drives. CIFS is the name of an early version of SMB.

Key takeaways

SMB is how Windows users share files over a network.
SMB permissions follow Windows access control lists tied to Active Directory.
Modern SMB versions add encryption, and SMB 1 should be turned off.

Why does SMB matter for unstructured data?

Because most office data lives on SMB shares: documents, spreadsheets, home folders, and department drives. These shares are also where dark data and orphaned files build up, since folders outlive the people and projects that created them. Any tool that indexes or governs that data reaches it over SMB.

What is an example of SMB in use?

A finance team opens a shared drive, mapped as a drive letter on every laptop, that points to a folder on the company’s NAS. Each person sees the folders their group is allowed to see, saves files there as if on a local disk, and finds the same files from any office.

What are the versions of SMB?

Three generations are in use:

SMB 1: the original version, which includes CIFS. It is old and insecure, and modern Windows turns it off by default.
SMB 2: much faster, with fewer messages for each operation.
SMB 3 and later: adds encryption, the use of several network paths at once, and better failover, and is the version to use today.

How do SMB permissions work?

SMB uses Windows access control lists: each file and folder lists which users and groups may read, change, or own it. Users and groups are identified by Active Directory, and the share itself can add a second layer of permissions on top. Indexers record owners as Windows security identifiers and look them up in Active Directory to show names and departments.

Is SMB secure?

Modern SMB can be, when it is set up well. The main steps are turning off SMB 1, which attacks such as WannaCry in 2017 spread through; using SMB 3 with signing and encryption; never exposing SMB shares directly to the internet; and keeping permissions tight, since broad access rights let malware reach more files.

Can the same files be shared over SMB and NFS?

Yes. Many NAS systems are multiprotocol: one share is available to Windows users over SMB and to Linux servers over NFS at the same time. The challenge is permissions, because SMB uses access control lists and named identities while NFS often uses ID numbers, so the storage system has to map one to the other consistently.

How does Diskover help?

Diskover scans SMB shares alongside NFS shares, object storage, and the cloud, and looks up Windows owners in Active Directory, so every file in the catalog shows a named owner.

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