BIND 9.3.2 Release Notes

multiple records in a response, it is useful to configure the order of the records placed
into the response.
Following is the syntax of the rrset-order option:
rrset-order {order_spec};
Where, an order_spec can be defined as follows:
[class class_name]
[ type type_name ]
[ name domain_name]
order ordering
The default value for class and type is ANY, and for name is *.
The valid values for ordering are:
fixed Records are returned in the order they are defined in the zone file
random
Records are returned in a random order
cyclic
Records are returned in a round-robin order
Following is an example of the rrset-order option:
rrset-order {
class IN type A name "host.example.com" order random;
order cyclic;
};
This rrset-order option causes responses for type A records in class IN that have
host.example.com as a suffix, to be returned in random order. Other types of records
are returned in cyclic order.
If the options statement contains multiple rrset-order options, they are not
combined but only the last rrset-order option is used.
New Option to Set the Advertized EDNS UDP Buffer Size
The edns-udp-size option in the options statement sets the advertised Extended
DNS (EDNS) User Datagram Protocol (UDP) buffer size to enable UDP answers to pass
through broken firewalls that block fragmented packets greater than 512 bytes. The
valid range of values is 512 to 4096 bytes (values not in this range are adjusted
appropriately). The default value of this option is 4096 bytes.
New Option to Restrict the Character Set of Domain Names
This check-names option in the options statement restricts the character set and
syntax of certain domain names in the master files and DNS responses. The rules for
valid host names or mail domains are derived from RFC 952 (DoD Internet Host Table
Specification) and RFC 821 (Simple Mail Transfer Protocol) as modified by RFC 1123
(Requirements for Internet Hosts - Application and Support). The check-names option
checks the names of the owner names of A, AAAA, and MX records and also checks
BIND 9.3.2 Features 11