Windows NT WinSock Listen (Backlog) Parameter Limit

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Article ID: 127144 - View products that this article applies to.
This article was previously published under Q127144
The WinSock listen() call backlog parameter under Windows NT version 3.5 and 3.51 accepts a maximum value of 100.

The maximum backlog parameter is 5 on Windows NT 4.0 Workstation, and 200 on Windows NT 4.0 Server.

WinSock server applications use the listen() call to establish a socket for listening for incoming connections. This calls second parameter, backlog, is defined as the maximum length to which the queue of pending connections may grow.

The WinSock version 1.1 specification states the maximum value for the backlog parameter is 5. However, Windows NT version 3.5 accepts up to 100 for this value.

Services that handle a large number of socket connections may be written to use a larger backlog value to prevent client connection requests from being dropped. This can be useful when writing applications such as World Wide WEB (WWW) and gopher servers.
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Article ID: 127144 - Last Review: November 1, 2006 - Revision: 2.1
  • Microsoft Windows NT Workstation 3.5
  • Microsoft Windows NT Workstation 3.51
  • Microsoft Windows NT Workstation 4.0 Developer Edition
  • Microsoft Windows NT Server 3.5
  • Microsoft Windows NT Server 3.51
  • Microsoft Windows NT Server 4.0 Standard Edition
kbapi kbnetwork kbwinsock KB127144

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