If you configure the Ethernet TCPWindowSize per interface with a value >=64240, it will use 17520 instead.

To workaround the problem, set the TCPWindowSize globally or use a value <64240.

To set the value of TCPWindowSize globally, use Regedt32 to navigate to:


To set it per interface:


Set this REG_DWORD data type to a multiple of 1460, the Ethernet Maximum Segment Size (MSS).

NOTE: TCPWindowSize is the maximum TCP receive window size, the number of bytes that a sender can transmit without receiving an acknowledgment.