401从ASP.NET Web应用程序联系ASP.NET Web服务时未经授权

I have a single server (Windows 2003/IIS 6). This server has a few different "Web Sites" setup in IIS. Each site is configured in IIS with a distinct host header (port 80). In addition, each site also is accessible over a specified port number (without host header).I have a single server (Windows 2003/IIS 6). Th