Not all Winsock behaviors are documented in the spec or in the MSDN Library. Here’s a list of interesting things I’ve found in Microsoft’s Knowledge Base.

How-Tos

KB314053, “TCP/IP & NBT Configuration Parameters for Windows XP” – This article documents all the registry tunables that the Windows XP TCP/IP stack uses, such as the MTU size. It apparently still applies through Windows 7, current as I write this. There are older articles for Windows 98/ME and Windows NT/2000.

KB190351, “Spawn Console Processes with Redirected Standard Handles” – It’s possible to redirect the standard I/O handles (stdin, stdout, stderr) to a socket, by way of the CreateProcess() API.

KB131978, “Receive/Send Multicasts Under WinNT/Win95 Using WinSock” – The title says it all.

Interesting Features

KB142641, “Internet Server Unavailable Because of Malicious SYN Attacks” – This article was written in 1996 in response to the first SYN flood attacks. It describes a new feature Microsoft added to Windows NT Server in subsequent service packs called the “dynamic backlog.” This feature changes how the listen() backlog parameter works. (See this FAQ item for more on connection backlogs.)

KB193059, “IP Helper APIs Add Net Config and Stat Info to Win32 Apps” – This article discusses the IP Helper APIs in newer versions of Windows. These aren’t strictly Winsock, but they make many Winsock tasks easier, and some previously-impossible ones easy.

KB164249, “Autodial Heuristics” – This article explains how the RAS system on modern versions of Windows chooses when to automatically bring up a modem link with its autodial feature. (Behavior is different with DUN in Chicago kernel versions of Windows.)