The urlMappings section contains System.Web.Configuration.UrlMapping objects that map URLs that are displayed to users to URLs that exist in your Web application. The System.Web.Configuration.UrlMappingsSection can write information into the related section of the configuration file according to the restrictions defined by the section property System.Configuration.SectionInformation.AllowDefinition whose value is System.Configuration.ConfigurationAllowDefinition.MachineToApplication. Any attempt to write in a configuration file at a level not allowed in the hierarchy will result in an error message generated by the parser. However, you can use this class to read configuration information at any level in the hierarchy.