Windows 11 • Release: 6 Benchmark Date: 05 Jan 2026
CAT II V-253353 WN11-CC-000020
IPv6 source routing must be configured to highest protection.
Discussion
Configuring the system to disable IPv6 source routing protects against spoofing.
Check Procedure
If the following registry value does not exist or is not configured as specified, this is a finding: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters\ Value Name: DisableIpSourceRouting Value Type: REG_DWORD Value: 2
Fix Action
Configure the policy value for Computer Configuration >> Administrative Templates >> MSS (Legacy) >> "MSS: (DisableIPSourceRouting IPv6) IP source routing protection level (protects against packet spoofing)" to "Highest protection, source routing is completely disabled". This policy setting requires the installation of the MSS-Legacy custom templates included with the STIG package. "MSS-Legacy.admx" and "MSS-Legacy.adml" must be copied to the \Windows\PolicyDefinitions and \Windows\PolicyDefinitions\en-US directories respectively.