“Windows 11 Insider Preview Build 25992 introduces significant changes to the Server Message Block (SMB) protocol, enhancing network security and offering more flexibility. The update includes SMB firewall rule changes, SMB NTLM blocking exception list, and alternative client and server ports.”

Introducing Windows 11 Insider Preview Build 25992

Exciting news for Windows Insiders! The latest Windows 11 Insider Preview Build 25992 has been released to the Canary Channel. This update brings a slew of new features and changes, particularly to the Server Message Block (SMB) protocol.

What’s New in Build 25992?

Windows 11 Insider Preview Build 25992 introduces significant changes to the SMB protocol. These changes are designed to enhance network security and offer more flexibility to administrators.

SMB Firewall Rule Changes

Creating SMB shares now changes a long-standing Windows Defender Firewall default behavior. Instead of enabling the rules in the “File and Printer Sharing” group, Windows now configures the new “File and Printer Sharing (Restrictive)” group. This change brings SMB firewall rules closer to the Windows Server “File Server” role behavior.

“This change enforces a higher degree of default of network security…”

SMB NTLM Blocking Exception List

The new SMB NTLM blocking feature now supports specifying exception lists for NTLM usage. This allows administrators to configure a general block on NTLM usage while still allowing clients to use NTLM for specific servers that do not support Kerberos.

SMB Alternative Client and Server Ports

The SMB client now supports connecting to an SMB server over TCP, QUIC, or RDMA using alternative network ports. This feature offers more flexibility to administrators and users, and can be completely disabled with a group policy if necessary.

“The SMB client now supports connecting to an SMB server over TCP, QUIC, or RDMA using alternative network ports.”

With these new features and changes, Windows 11 Insider Preview Build 25992 is set to enhance network security and offer more control to administrators. Stay tuned for more updates from the Canary Channel!

New SMB firewall rule changes enhance network security and align with Windows Server “File Server” role behavior.

SMB NTLM blocking feature now supports exception lists, allowing specific servers to use NTLM.

SMB client now supports connection to an SMB server over TCP, QUIC, or RDMA using alternative network ports.

Administrators can modify the new firewall group and the “File and Printer Sharing” group if necessary.

The SMB over QUIC server in Windows Server supports endpoints configured with different ports than 443.

From the Windows Blog

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