Since sing-box 1.12.0

Predefined

Structure

{
  "dns": {
    "servers": [
      {
        "type": "predefined",
        "tag": "",
        "responses": []
      }
    ]
  }
}

Fields

responses

Required

List of Response.

Response Structure

{
  "query": [],
  "query_type": [],
  "rcode": "",
  "answer": [],
  "ns": [],
  "extra": []
}

You can ignore the JSON Array [] tag when the content is only one item

Response Fields

query

List of domain name to match.

query_type

List of query type to match.

rcode

The response code.

Value	Value in the legacy rcode server	Description
NOERROR	success	Ok
FORMERR	format_error	Bad request
SERVFAIL	server_failure	Server failure
NXDOMAIN	name_error	Not found
NOTIMP	not_implemented	Not implemented
REFUSED	refused	Refused

NOERROR will be used by default.

answer

List of text DNS record to respond as answers.

Examples:

Record Type	Example
A	localhost. IN A 127.0.0.1
AAAA	localhost. IN AAAA ::1
TXT	localhost. IN TXT \"Hello\"

ns

List of text DNS record to respond as name servers.

extra

List of text DNS record to respond as extra records.