Setting SharePoint 2010 site public URL using Alternate Access Mapping & Host Header Setting

1.In Iss select the sharepoint site > Edit Bindings

provide the host name say "myportal.site.com"

2.Configure Alternate Access Mapping

Go to Central Admin > Application Management > Alternate Access Mappings

Edit Public URLs add the site "http://myportal.site.com"

3. Refer this link to solve the error 401.1 error when you try from the same server

(from different system the link will work fine).