Knowledge Base

Ambiguous site selection message when profiling IIS applications

Category: Troubleshooting & error messages
Date: 24 Mar 2009
Product: ANTS Profiler
Fix version: 4.3 (Performance only)

When ANTS Profiler is asked to profile an edition of IIS that support multiple websites (IIS 6, 7), it may report an "Ambiguous Site Selection" error when multiple sites are bound to TCP port 80.

Because ANTS Profiler needs to extract information about the web application being profiled from the IIS configuration so that it loads the correct physical directory and uses the correct .NET Framework version, it needs to know which web application will be loaded when it would normally be accessed at the URL listed in ANTS Profiler's "Address" box. It does this using the "bindings" information in the IIS configuration.

If two websites are bound to TCP port 80, regardless of the host header or IP address information, the site is assumed to be ambiguous by ANTS Profiler and the profiling cannot begin.

A workaround is to "temporarily" bind one or the websites in question to a different TCP port for the purposes of profiling. The instructions for setting bindings in IIS can be found in Microsoft Internet Information Server's documentation.

Please note that this bug has been addressed in Performance Profiler version 4.3 and this problem should no longer occur after upgrading. The memory profiler is still affected.