Virtual web applications provide an integration of existing web applications from web-based content providers, such as the Microsoft SharePoint 2007 server, with IBM® WebSphere Portal through a web application proxy. After the web applications are provisioned on the Manage web application portlet, Administrators use a lightweight IFrame portlet to host the applications, which users can then access on a portal page without requiring direct network access to the content. A special engine on the portal makes this possible by mapping Uniform Resource Identifiers (URI) on the portal to real URI on the content providers.