Auth constraint

[anoop]

hi all,   in Tomcat how do i use this feature in web.xml.           <auth-constraint>          <!-- Anyone with one of the listed roles may access this area -->          <role-name>tomcat</role-name>   <role-name>role1</role-name>       </auth-constraint>   how do i set a role-name with its passwd etc..   thanx in adv, regards, anoop