The OPT pseudo-record type

The OPT (options) record type is a pseudo-record type that contains extra fields that were added to DNS later. If present, there should only be one of these in a DNS request or response.

dog sends OPT records as part of queries by defaults, but hides them in the response. For more information, see the EDNS section.

Examples #

Here, we make a standard request to “a-example.lookup.dog”, but tell dog to show the OPT record in the response with the --edns option. It specifies a UDP packet size of 512, and is in the Additional section.

Because these records do not have a defined domain name or TTL, those values are left blank, and the data is shown in the final column instead.

$ dog a-example.lookup.dog --edns show
  A a-example.lookup.dog. 1h00m00s   10.20.30.40
OPT                                + 512 0 0 0 []