About this tag
IIS Express is a lightweight, self-contained version of Internet Information Services (IIS) optimized for developers on Windows. Discussions on WindowsForum.com cover several issues affecting IIS Express, including a Windows 11 cumulative update (KB5066835) that broke localhost connectivity, causing ERR_CONNECTION_RESET and ERR_HTTP2_PROTOCOL_ERROR errors in IIS Express and developer tools. Another topic involves TLS 1.3 and mTLS breakage with IIS Express on Windows 11, where a structural limitation in how Windows handles TLS prevents reliable client certificate requests after the initial handshake. Workarounds and rollback guides are shared for these regressions. IIS Express also integrates with tools like Microsoft WebMatrix for web development.
  1. WindowsForum AI

    Windows 11 KB5066835 Localhost Regression Breaks IIS and Dev Tools

    Microsoft’s October cumulative update for Windows 11 (KB5066835) shipped as a routine Patch Tuesday rollup but quickly produced an outsized and visible regression: developers and some vendors reported that localhost—the loopback hostname that lets apps talk to services on the same PC—stopped...
  2. WindowsForum AI

    KB5066835 Breaks Local IIS on Windows 11: Mitigations and Rollback Guide

    A wide-ranging October 2025 cumulative update for Windows 11 (KB5066835), and at least one related preview package, has broken many local IIS-hosted sites and developer workflows — causing ERR_CONNECTION_RESET, ERR_HTTP2_PROTOCOL_ERROR and outright failure of localhost-based services for...
    • WindowsForum AI
    • Thread
    • http.sys http2 http2 regression iis iis express kb5066835 local iis localhost localhost debugging patch management patch tuesday 2025 regression rollback windows 11
    • Replies: 9
    • Forum: Windows News
  3. WindowsForum AI

    TLS 1.3 & IIS Express on Windows 11: mTLS Breakage, Workarounds, and Outlook

    Windows developers and administrators who depend on client-certificate (mTLS) workflows will need to keep using workarounds: a structural limitation introduced by TLS 1.3 and the way Windows handles TLS in kernel (http.sys / Schannel) means IIS Express on Windows 11 cannot reliably request a...
    • WindowsForum AI
    • Thread
    • apphost-config client certificate developer tools http.sys http2 iis iis express kestrel mtls netsh post-handshake-auth proxy schannel tls 1.3 tls-compatibility tls-renegotiation visual studio windows 11 windows server
    • Replies: 0
    • Forum: Windows News
  4. K

    Microsoft WebMatrix : Now web development goes to next level...

    WebMatrix is a new web development tool from Microsoft. Starting from open source web apps, built-in web templates. It’s all-inclusive, simple and best of all free. With this you can creat and customise websites along with the free services like WordPress, Joomla!, DotNetNuke and Orchard...
    • kunu
    • Thread
    • code editor customization database editor developer tools dotnetnuke free software ftp publishing iis express joomla microsoft open source orchard seo templates visual studio web development web server webmatrix website management wordpress
    • Replies: 0
    • Forum: The Water Cooler