Understanding Host-Named Site Collections

In SharePoint, host-named site collections provide a scalable hosting solution with distinct host names or URLs for accessing specific site collections. This allows a user to access a specific root-level site collection using a unique URL, a concept commonly referred to as a “vanity” URL. A single web application can support up to 100,000 host-named site collections. Host-named site collections are only available through the default security zone. Also, users authenticated through other zones cannot access host-named site collections.

In SharePoint 2010, host-named site collections support off-box SSL termination. With host-named site collections, the reverse proxy server cannot modify the host name or the port number (except to 80 and 443 for SSL). Administration of host-named site collections is available through Windows PowerShell commands.