asp v2.0 iis7 machine.config amended to contain maxconnection="192" stopped calls working to third party web services - asp.net

Question

I added the following to:
C:\Windows\Microsoft.NET\Framework64\v2.0.50727\CONFIG\machine.config
<system.net>
<connectionManagement>
<add address="*" maxconnection="192" />
</connectionManagement>
</system.net>
After saving the application was running fine. However calls to third party web services/web method (MICROSOFT MAPPOINT, another API unrelated to Microsoft i.e two independent references) failed to work. One of which returned the following error:
--------------------------------------
Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:
[NullReferenceException: Object reference not set to an instance of an object.]
WebApp.AddUpdate.LoadWebServiceRecord() +7740
WebApp.AddUpdate.MessageBox1_YesClicked(Object sender, EventArgs e) +51
WebApp.webcontrols.MessageBox.Yes_Click(Object sender, EventArgs e) +140
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +114
System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +139
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +28
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2980
Version Information: Microsoft .NET Framework Version:2.0.50727.4206; ASP.NET Version:2.0.50727.4209
i.e exception above appears to have been created as it could no longer contact the service.
Remove the amendment in machine.config i.e remove the maxconnection rows and it all works fine again. Any idea why?
Do i need to declare the third party reference's in maxconnection?
if so would it be possible to provide and example?

Answer 1

Generally speaking, you shouldn't have to adjust it manually. ASP.NET 2 sets processModel to auto by default which among other things automatically scales maxconnections for the # of CPUs available (12N).
As to the error you're seeing, there must be more than meets than eye; the two are completely unrelated and there is no reason any maxconnection value would trigger a NullReferenceException in your application.
HTH
References:
http://technet.microsoft.com/en-us/magazine/2006.11.insidemscom.aspx
http://msdn.microsoft.com/en-us/library/7w2sway1.aspx