Thanks for your reply
here i explain what i do exactly
SiteManager->Edit Site ->Domain Aliases->New Domain Alias
Domain Alias : state.maadnews.com
Default alias path: /States/States (real page)
Redirect URL : ""
now for placeholder page (states)
Properties->Menu->URL redirection: state.maadnews.com
after doing these settings nothing happens.
Note that i don't have a sub domain named "http://state.maadnews.com"
where is my mistake?
and if this is server side or iis setting issue how i can solve it