smb-durable-handle · shipping · also SMB durable open

SMB durable handle

An SMB durable handle allows a client to attempt to recover an existing file open after a network disconnect.

Related Observatory article: SMB durable handle on hesela.com

The server retains reconnectable open state subject to a timeout and original-opener authorization. It does not keep the old transport connection alive indefinitely. [2] Re-establishment uses a CREATE request with a reconnect context; the SMB 3.x form also carries the create identifier and, for a persistent open, the persistent flag. [3] Recovering this state is not by itself proof that every application write is on stable storage: the protocol defines write-through separately. [4]

Relations

related

smb-protocol, smb-persistent-handle, smb-lease, io-timeout

Citations

1. Microsoft MS-SMB2 section 1.1: Glossary (accessed 2026-10-13)
2. Microsoft MS-SMB2 section 3.3.1.10: Per Open (accessed 2026-10-13)
3. Microsoft MS-SMB2 section 3.2.4.4: Re-establishing a Durable Open (accessed 2026-10-13)
4. Microsoft MS-SMB2 section 2.2.21: SMB2 WRITE Request (accessed 2026-10-13)

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