Ports used by ReportViewer web controls

When a ReportViewer control is used to access a report on a remote SQL Server database, on what ports does the communcation occur? Does the control communicate on on the SQL Server ports of 1433 and 1434 or does it communcate as a web service on port 80 (or 443 for HTPPS)?It will depend on the url that you set for the report server. For a standard url it will use 80 (and 443), however you can always pass in a url for a non-standard port.