Alternative Port Mappings

Policy ID
Pol_AlternativePortMappings
Scope
Computer Configuration
Supported on
At least Windows Server 2025, Windows 11
Source
Administrative Templates (.admx) for Windows 11 2026 Update (26H2) (version 1.0)
Category
Network › Lanman Workstation

Description

This policy setting determines the alternative port registry mappings used by the SMB client.

If you enable this policy setting, the first valid mapping will be used if the mapping's server name matches the targeted server name for connectivity.

If you enable this policy setting and do not specify at least one valid mapping, or if you disable or do not configure this policy setting, then the SMB client will refer to other methods of determining alternative port usage such as with the NET USE or New-SmbMapping commands.

Examples:

contososa.file.core.windows.net:tcp:448
edgesrv1.corp.contoso.com:quic:450

How to modify this setting:

Arrange the desired alternative port mappings in the edit box with one mapping entry per line.

The format of each mapping entry specifies a server name, transport type, and port number separated by colons as done so in the example above.

Note: This policy does not require a Windows reboot to take effect.

Options

  • Alternative Port Registry Mappings:

Registry

ComputerHKEY_LOCAL_MACHINE
  • AlternativePortMappingsREG_MULTI_SZ

Other policies in the same category

View all policies in this category (19)