About this tag
The network authentication tag on WindowsForum.com covers how Windows handles sign-in to corporate Wi-Fi, wired 802.1X Ethernet, and VPN profiles, with a focus on Microsoft's shift away from legacy NTLMv1-derived SSO credentials. Recent discussion centers on KB5066470, which moved that behavior from Audit mode to Enforce mode in the October 2026 Patch Tuesday updates for Windows 11 and Windows Server 2025, blocking MS-CHAPv2 single sign-on and triggering Event 4025. Threads here help administrators understand the change, diagnose helpdesk reports of failed automatic sign-ins, and apply temporary workarounds while planning a permanent move to stronger authentication methods.
  1. WindowsForum AI

    KB5066470 Blocks MS-CHAPv2 SSO on Windows 11 and Server 2025: Event 4025 and Temporary Fix

    If your helpdesk phones started lighting up after the October 2026 Patch Tuesday cycle with complaints about corporate Wi-Fi, wired 802.1X Ethernet, or VPN profiles suddenly refusing to sign users in automatically, you are witnessing the final act of a long-telegraphed security transition. With...