java.net.SocketException: Connection reset

[DannyT]

Firstly apologies for reposting the same question I already asked here. However, I feel I over-complicated the question by not really understanding the issue which I can now outline in short:-

Master and Slave (both win2k8 servers) have no firewall restrictions between each other.

I have set the slave jnlp port to fixed at 2000

Slave errors on handshaking as follows:

03-Oct-2011 15:07:22 hudson.remoting.jnlp.Main$CuiListener <init>
INFO: Hudson agent is running in headless mode.
03-Oct-2011 15:07:22 hudson.remoting.jnlp.Main$CuiListener status
INFO: Locating server among [http://myserver:8080/]
03-Oct-2011 15:07:22 hudson.remoting.jnlp.Main$CuiListener status
INFO: Connecting to myserver:2000
03-Oct-2011 15:07:22 hudson.remoting.jnlp.Main$CuiListener status
INFO: Handshaking
03-Oct-2011 15:08:23 hudson.remoting.jnlp.Main$CuiListener error
SEVERE: Connection reset
java.net.SocketException: Connection reset
        at java.net.SocketInputStream.read(Unknown Source)
        at java.io.BufferedInputStream.fill(Unknown Source)
        at java.io.BufferedInputStream.read(Unknown Source)
        at hudson.remoting.Engine.readLine(Engine.java:279)
        at hudson.remoting.Engine.run(Engine.java:211)

Server log as such:

INFO: Accepted connection #13 from /MY.SLAVE.IP.ADDRESS:58545
Oct 3, 2011 5:38:09 PM hudson.TcpSlaveAgentListener$ConnectionHandler run
WARNING: Connection #13 failed
java.net.SocketException: Connection reset
    at java.net.SocketInputStream.read(Unknown Source)
    at java.net.SocketInputStream.read(Unknown Source)
    at java.io.DataInputStream.readUnsignedShort(Unknown Source)
    at java.io.DataInputStream.readUTF(Unknown Source)
    at java.io.DataInputStream.readUTF(Unknown Source)
    at hudson.TcpSlaveAgentListener$ConnectionHandler.run(TcpSlaveAgentListener.java:178)

Setting the fixed port to 6060 works without issue.

I can telnet from slave to master over port 2000 so i'm sure there is nothing using that already.

What could be killing the connection or what can I do to find out more information?