A.7.1 Syntax

     zones {
       [ zone_options ]
       zone_id {
         file "string";
         [ xfr-in remote_id [, remote_id, ... ]; ]
         [ xfr-out remote_id [, remote_id, ... ]; ]
         [ notify-in remote_id [, remote_id, ... ]; ]
         [ notify-out remote_id [, remote_id, ... ]; ]
         [ update-in remote_id [, remote_id, ... ]; ]
         [ zone_options ]
       }
     }
     
     zone_options :=
       [ semantic-checks boolean; ]
       [ ixfr-from-differences boolean; ]
       [ disable-any boolean; ]
       [ notify-timeout integer; ]
       [ notify-retries integer; ]
       [ zonefile-sync ( integer | integer(s | m | h | d); ) ]
       [ ixfr-fslimit ( integer | integer(k | M | G) ); ]
       [ ixfr-from-differences boolean; ]