Expand description
DNS response codes and extended response codes.
The original DNS specification in RFC 1035 specified four bits of the
message header as response code. The type Rcode defined herein
represents these codes. Later, RFC 2671 (now RFC 6891) added eight
bits to the response code to be transmitted as part of the OPT
pseudo-resource record. To make matters even worse, the TSIG and TKEY
records defined by RFC 2845 and RFC 2930 use a 16 bit error code.
All of these codes share the same definition space. Even so, we have
separate types for each of these.