Which is the default TCP connect timeout in Windows? There is a registry key to configure it or it's set dynamically?
In Windows the value is dynamic for established conections, though the default for initial connections is 72 seconds. The Registry settings are defined in this article:
HKEY_LOCAL_MACHINE \SYSTEM \CurrentControlSet \Services: \Tcpip \Parameters
TcpInitialRTT: Defines what the initial time-out settings are for new connections. This number in seconds is doubled each time it retransmits before timing a connection out. Defaults to 3.
TcpMaxConnectRetransmissions: Defines the number of retransmissions before timing a connection out. Defaults to 5.
TcpInitialRTT and TcpMaxConnectRetransmissions may not be present in Vista and Windows 2008. This Microsoft document does not include them. http://download.microsoft.com/download/c/2/6/c26893a6-46c7-4b5c-b287-830216597340/TCPIP_Reg.doc
And this says at least TcpInitialRTT is gone, although I don't know how reliable it is. http://pul.se/Blog-Post-TCP-IP-Stack-hardening-in-Operating-Systems-starting-with-Windows-Vista_SharePoint-kHPTTCP0WJ5,7zq00hH0wINE