I personally got this problem on my laptop a while ago where IIS and Skype where involved, and even if this time the customer reported two different applications involved (Visual Studio 2005 and Cisco IP Communicator), the symptoms where the same: with Visual Studio 2005 and Cisco IP Communicator running ad the same time, he was unable to debug his web application with the message “Unable to start debugging on the web server. Could not start ASP.NET or ATL Server debugging. Verify that ASP.NET or ATL Server is correctly installed on the server“. If he stopped the IP Communicator the problem went away; clearly a conflict between IIS and Cisco Communicator.
Just to be sure we had a look at “netstat -a -b”, and found (as expected) that both applications were listening on the HTTP port
TCP computername:http computername.domain.com:0 LISTENING 492 [inetinfo.exe]
TCP computername:http computername.domain.com:0 LISTENING 3872 [Communicator.exe]
Since I don’t know how Cisco IP Communicator works (and we can’t support third party apps anyway), we decided to change the IIS port to 81, but this time the customer was getting “Unable to start debugging on the web server. Unable to connect to the web server. Verify that the web server is running and that incoming HTTP requests are not blocked by a firewall“. Another tweak on customers firewall and the problem was fully resolved.
Carlo
Quote of the Day:
He is poor who does not feel content.
–Japanese proverb