TCP Socket TIME_WAIT error Windows WCF

Hi,

I've setup HAProxy (version 1.3.15.2 from repo's) on Debian to load balance requests to a bunch of Windows web services running on IIS7. My problem is that after load testing the system, Windows runs out of sockets as they all end up in the TCP TIME_WAIT state. (Nice explanation of this TCP state found here:
http://blog.zhuzhaoyuan.com/2009/03/a-word-on-time_wait-and-close_wait/)

When removing the load balancer and having the requests go directly to the web server there are only a maximum of 10 sockets in the TIME_WAIT state at any one time.

It seems like there's some error in communication between HAProxy and Windows/IIS7 where the sockets aren't closed properly. I've tried adding the "httpclose" option but the problem remained. Has anyone had this problem before? My haproxy.cfg is as below:

global

        log 127.0.0.1   local0
        log 127.0.0.1   local1 notice


        #log loghost    local0 info

        maxconn 40960


        #chroot /usr/share/haproxy

        user haproxy
        group haproxy
        daemon


        #debug

        #quiet


defaults
        log     global
        mode    http
        option  httplog
        option  dontlognull
        retries 3
        option redispatch
        maxconn 2000
        contimeout      5000
        clitimeout      50000
        srvtimeout      50000

listen webfarm 192.168.17.150:80
        mode http
        stats enable
        stats auth admin:admin
        balance roundrobin
        option httpchk
        option httpclose
        http-check disable-on-404
        server dn1 192.168.17.136 check
        server dn2 192.168.17.137 check
        server dn3 192.168.17.138 check

Thank you

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