I have deployed a new version of an ASP.NET webservice. The IIS logfile reports an errorcode 500 when this service is being called by a client. My own (test) can use the service without any error. I have enabled errorlogging in my ASP.NET webservice, but no error is being logged, which leads me to believe the error is not thrown by my code, but somewhere 'earlier' in the stack. I have also examined the httperr1.log file but there's nothing relevant there.
Question, how can I add more errorlogging to IIS to investigate the error? I have no access to the client.
[Updates] I'm using IIS6. I've checked the eventlog and found nothing there.
DebugDiag 2.0 from Microsoft is the definite tool you want to use if you are on IIS6.
Which version of IIS are you using?
In IIS7 you have extensive tracing capabilities.
Take a look at: Troubleshooting Failed Requests Using Tracing in IIS 7.0
In what format is your logfile? IIS format often contains error messages from a specific request while the default format doesn't.
If you run the webMethod from the auto generated proxy on the localhost, you can see the stack trace dump, when it crashes.
来源：https://stackoverflow.com/questions/557490/how-can-i-trace-iis-500-errors-thrown-by-my-webservice