BIND Configuration File Guide--server Statement

server ip_addr {
  [ bogus yes_or_no; ]
  [ transfers number; ]
  [ transfer-format ( one-answer | many-answers ); ]
  [ keys { key_id [key_id ... ] }; ]
};

The server statement defines the characteristics to be associated with a remote name server.

If you discover that a server is giving out bad data, marking it as bogus will prevent further queries to it. The default value of bogus is no.

The server supports two zone transfer methods. The first, one-answer, uses one DNS message per resource record transferred. many-answers packs as many resource records as possible into a message. many-answers is more efficient, but is only known to be understood by BIND 8.1 and patched versions of BIND 4.9.5. You can specify which method to use for a server with the transfer-format option. If transfer-format is not specified, the transfer-format specified by the options statement will be used.

The transfers will be used in a future release of the server to limit the number of concurrent in-bound zone transfers from the specified server. It is checked for syntax but is otherwise ignored.

The keys statement is intended for future use by the server. It is checked for syntax but is otherwise ignored.