nginx upstream server "out of ports"

I'm using nginx as reverse proxy, and find more than 30k TIME_WAIT state ports in upstream server(windows 2003). I know my servers are "out of ports" which discussed here(http://nginx.org/pipermail/nginx/2009-April/011255.html), and set both nginx and upstream server to reuse TIME_WAIT and to recycle more quickly.

[sysctl -p]
……
net.ipv4.ip_local_port_range = 1024 65000
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 1

But nginx hangs and "connection timed out while connection to upstream server" error still can be found on nginx error log, when RPS of upstream is higher than 1000 within 1 minutes. When upstream is Windows, server will be "out of ports" in seconds.

Any ideas? A connection pool with a waiting queue? Maxim Dounin wrote a useful module to keep connection with memcached, but why can't it support Web Server?

I am new to nginx but from what I know so far, you need to reduce your net.ipv4.tcp_fin_timeout value which defaults to 60 seconds. Out of the box nginx doesn't supports http connection pooling with backend. Because of this every request to backend creates a new connection. With 64K ports and 60 seconds of wait before that port can be reused, the average RPS will not be more than 1K per second. You can either reduce your net.ipv4.tcp_fin_timeout value both at nginx server and the backend server or you can assign multiple ip addresses to the backend box and configure nginx to treat these "same servers" as different servers.