Apache > HTTP Server > Documentation > Version 2.4 > Modules

Apache MPM winnt

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Description:Multi-Processing Module optimized for Windows NT.
Module Identifier:mpm_winnt_module
Source File:mpm_winnt.c


This Multi-Processing Module (MPM) is the default for the Windows NT operating systems. It uses a single control process which launches a single child process which in turn creates threads to handle requests

Capacity is configured using the ThreadsPerChild directive, which sets the maximum number of concurrent client connections.

By default, this MPM uses advanced Windows APIs for accepting new client connections. In some configurations, third-party products may interfere with this implementation, with the following messages written to the web server log:

Child: Encountered too many AcceptEx faults accepting client connections.
winnt_mpm: falling back to 'AcceptFilter none'.

The MPM falls back to a safer implementation, but some client requests were not processed correctly. In order to avoid this error, use AcceptFilter with accept filter none.

AcceptFilter http none
AcceptFilter https none

In Apache httpd 2.0 and 2.2, Win32DisableAcceptEx was used for this purpose.

The WinNT MPM differs from the Unix MPMs such as worker and event in several areas:

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