how to start a huge amount of tcp client connections - sockets

Question

　　　　　　　　　　　　　　　　　　　　　　　　　Happy Spring Festival - the Chinese New Year.
I'm working on server programming, and stucked in 10055 Error.
I have a TCP client application, which can simulate a huge amount of clients.
Hearing that 65534 is the maximum value of tcp client connections of one computer,
I use Asio to implement simulation client which start 50000 asynchronous tcp connects.
pseudocode:
for (int i=0: i<50000 ; ++i)
asyn_connect(...);
Development Environment is:
windows xp , x86 , 4G memory, 4 core CPU
HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\MaxUserPort=65000
The result is:
when connects come up to 17000 , 10055 Error occur.
I tried another computer ,the Error occur at 30000 connections, better but not enough good.
( the server app runs at another computer, also using Asio ).
The question is:
How to successfully start 50000 client connections at one computer?

Answer 1

Cou could try to do it more blockwise:
Eg. start with 10000 connections. As soon as 5000 connections were successful start the next 5000 async_connect calls. Then repeat that until you have reached your target. That would at least put less stress on the IO completion port. If it doesn't work I would try with even smaller blocks.
However depending on where the OS runs out of memory that still won't help.
Do you start asynchronous reads directly after the connect succeeds? These will also drain the memory resources.