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Windows CLAT Enters Private Preview: A Milestone for IPv6 Adoption

JimAlumbaugh's avatar
JimAlumbaugh
Icon for Microsoft rankMicrosoft
Nov 18, 2025

The journey to a fully IPv6-enabled Internet has been long, but today we celebrate a major milestone.

IPv6 Adoption: A Global Shift Since its standardization in the late 1990s, IPv6 has steadily gained traction. The last 15 years, especially since World IPv6 Launch Day in 2011, have seen significan...
Updated Nov 14, 2025
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DS128's avatar
DS128
Copper Contributor
Nov 19, 2025

Would be immensely helpful if MS weren't introducing new features without IPv6 support.

For instance Entra got v6 support a couple of years back, and it was working fine until the company enabled "mcas". Now the login process bounces through a legacy-only host which breaks v6-only operation:

$ host microsoft-com.access.mcas.ms
microsoft-com.access.mcas.ms is an alias for mps-mda-ic-bouncer-prd-weu.trafficmanager.net.
mps-mda-ic-bouncer-prd-weu.trafficmanager.net has address 20.254.168.148