Each web application can be associated with a collection of mappings between internal and public URLs. Both internal and public URLs consist of the protocol and domain portions of the full URL (for example, https://www.xxx.yyy.com). A public URL is what users type to access the SharePoint site, and that URL is what appears in the links on the pages. Internal URLs are in the URL requests that are sent to the SharePoint site. Many internal URLs can be associated with a single public URL in multi-server farms (for example, when a load balancer routes requests to specific IP addresses to various servers in the load-balancing cluster).