Salve a tutti,

non sono molto pratico per quanto riguarda la configurazione, vorrei qualche piccola spiegazione in merito al file server.xml di tomcat


codice:
 <Host appBase="webapps" autoDeploy="false" name="localhost" unpackWARs="true" xmlNamespaceAware="false" xmlValidation="false">
        <!-- SingleSignOn valve, share authentication between web applications
             Documentation at: /docs/config/valve.html -->
        <Valve className="org.apache.catalina.authenticator.SingleSignOn"/>
        <Realm className="org.apache.catalina.realm.CombinedRealm">
          <Realm className="org.apache.catalina.realm.JDBCRealm" connectionName="V_CNS" connectionPassword="svce" connectionURL="jdbc:oracle:thin:@cens-db:1521:cen" digest="SHA-256" driverName="oracle.jdbc.driver.OracleDriver" roleNameCol="profilo_app_l1" userCredCol="password" userNameCol="id_utente" userRoleTable="vc_ruoloutente" userTable="vc_utentepassword"/>
          <Realm className="org.apache.catalina.realm.JDBCRealm" connectionName="SV_SGRPES" connectionPassword="svsgrpes" connectionURL="jdbc:oracle:thin:@croazia1:1521:CRO1" digest="SHA-256" driverName="oracle.jdbc.driver.OracleDriver" roleNameCol="profilo_app_l1" userCredCol="password" userNameCol="id_utente" userRoleTable="vc_ruoloutente" userTable="vc_utentepassword"/>
          
          <Realm className="org.apache.catalina.realm.UserDatabaseRealm" resourceName="UserDatabase"/>
        </Realm>
        <!-- Access log processes all example.
             Documentation at: /docs/config/valve.html -->
        <!--
        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log." suffix=".txt" pattern="common" resolveHosts="false"/>
        -->
      </Host>
Che cosa significa in particolare il tag Realm e a cosa serve?

Sarei molto felice se potessi ricevere almeno queste informazioni

grazie