url rewrite

Question

the default url is (www.abcd.com/home.aspx) if i write (www.abcd.com/raj/home.aspx) , so it check the name (raj ) is present in data base or not if yes then url change as (www.abcd.com/raj/home.aspx) if not the it go to the default page (www.abcd.com/home.aspx)