How to enable tracing on WCF services to troubleshoot things like serialization errors

This is an excerpt from an article on MSDN on tracing. Details can be found there.
It will help you debug that annoying "The connection has been forcibly closed" error, that has no usefull information attached to it at all.

1. Add the following code in your web.config or app.config for the WCF service:
<configuration>
<system.diagnostics>
<sources>
<source name="System.ServiceModel"
switchValue="All"
propagateActivity="true">
<listeners>
<add name="traceListener"
type="System.Diagnostics.XmlWriterTraceListener"
initializeData= "c:\log\Traces.svclog" />
</listeners>
</source>
</sources>
</system.diagnostics>
</configuration>

This code should be added after the
<configSections>
element. Not doing so will cause an error.

Alternatively, use the configuration editor at Start -> All Programs -> Microsoft Windows SDK v6.0A -> Tools -> Service Configuration Editor to enable the diagnostics.

2. Make sure the "c:\log\" path is created and accessible to the appropriate accounts (I've just given the "everyone" account write access to it, but the .net worker process account would probably be enough)

3. Open the Traces.svclog file with the service traceviewer, which can be found here:

"C:\Program Files\Microsoft SDKs\Windows\v6.0A\bin\SvcTraceViewer.exe"

or go to Start -> All Programs -> Microsoft Windows SDK v6.0A -> Tools -> Service Trace Viewer

And that's it. The service viewer will show you any errors that was logged, and provides a very handy way to drill into the details.