Internet Information Services (IIS) is a web server created by Microsoft for use with Windows operating systems. IIS supports protocols like HTTP, HTTPS, FTP, and SMTP. It includes features like sites, applications, and virtual directories to organize and serve content. IIS can run in either classic or integrated mode, with integrated taking full advantage of newer IIS capabilities. Application pools allow isolating applications from one another for security and stability. IIS includes additional components like connection strings, settings, file types, and directories.