Web servers — IIS, Kestrel, Nginx and how ASP.NET is hosted — Networking & Hosting — How a Website Works, End to End

9. Web servers — IIS, Kestrel, Nginx and how ASP.NET is hosted

Intermediate★ Must knowLesson 9 of 12

Server	Platform	Notes
IIS	Windows	Hosts ASP.NET (Framework) in the `w3wp.exe` worker process; app pools, bindings, Windows auth, URL Rewrite
Kestrel	Cross-platform	ASP.NET Core's built-in, fast server; can face the internet directly or sit behind a reverse proxy
HTTP.sys	Windows	Kernel-mode HTTP driver; ASP.NET Core can use it directly
Nginx / Apache	Linux mostly	Reverse proxy and static file server in front of Kestrel, Node, PHP

IIS key concepts:

Site — bindings (protocol + IP + port + host name, e.g. https *:443 www.shop.com with a certificate).
Application pool — the worker process (w3wp.exe) running your app; isolation, identity (ApplicationPoolIdentity), recycling, .NET CLR version ("No Managed Code" for ASP.NET Core).
HTTP.sys receives requests in the kernel and queues them per app pool.
ASP.NET Core Module (ANCM) — runs ASP.NET Core in-process (inside w3wp, fastest) or out-of-process (IIS proxies to Kestrel).
web.config — module and handler settings; for Core it points IIS at dotnet YourApp.dll or the app's exe.

xml

<!-- web.config generated by dotnet publish for ASP.NET Core on IIS -->
<configuration>
  <system.webServer>
    <handlers><add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" /></handlers>
    <aspNetCore processPath="dotnet" arguments=".\Shop.Web.dll" stdoutLogEnabled="false" hostingModel="inprocess" />
  </system.webServer>
</configuration>