Windows NT WinSock Listen (Backlog) Parameter Limit

ID: Q127144

The information in this article applies to:

Microsoft Windows NT Workstation versions 3.5, 3.51, 4.0
Microsoft Windows NT Server versions 3.5, 3.51, 4.0

The WinSock listen() call backlog parameter under Windows NT version 3.5 and 3.51 accepts a maximum value of 100.

The backlog parameter on NT 4.0 Workstation is set to 5 while NT 4.0 Workstation and 200 on 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.

Additional query words: prodnt

Keywords : kbnetwork kbAPI kbSDKPlatform kbWinsock ntnetserv NTSrvWkst kbGrpNet
Version : 3.5 4.0
Platform : winnt
Issue type :