To configure alternate access mapping for
SharePoint Portal Server
On the SharePoint Portal Server computer, click Start,
point to All Programs, point to SharePoint Portal
Server, and click SharePoint Central
Administration.
Under Portal Site and Virtual Server Configuration,
click Configure alternate portal site URLs for intranet,
extranet and custom access.
Under Mapping Name, click the Web site and select
Edit.
Under Extranet URL, provide the public name for the
SharePoint Web site, such as https://portal.contoso.com.
Note
For more information on alternate access mapping see Alternate
Access Mapping(http://www.microsoft.com/)