How to determine which TCP port Analysis Services is listening on

While recently installing and interfacing SQL Server Analysis Services (SSAS) with Commerce Server 2009, I had to find out on which TCP port SSAS was listening on. This is a fairly common procedure as firewalls and CS2009 resources have to be configured. The technique is simple, but not necessarily intuitive:

  1. Open the file %PROGRAMFILES%\Microsoft SQL Server\90\Shared\ASConfig\msmdredir.ini or %PROGRAMFILES% (x86)\Microsoft SQL Server\90\Shared\ASConfig\msmdredir.ini (sur machine 64 bit)
  2. Find the <Instance> tag that matches your SSAS
  3. Read the value from the inner <Port> tag