sing-box/docs/configuration/dns/server/legacy.md

---

icon: material/delete-clock

!!! failure "Deprecated in sing-box 1.12.0"

Legacy DNS servers is deprecated and will be removed in sing-box 1.14.0, check [Migration](/migration/#migrate-to-new-dns-servers).

!!! quote "Changes in sing-box 1.9.0"

:material-plus: [client_subnet](#client_subnet)

Structure

{
  "dns": {
    "servers": [
      {
        "tag": "",
        "address": "",
        "address_resolver": "",
        "address_strategy": "",
        "strategy": "",
        "detour": "",
        "client_subnet": ""
      }
    ]
  }
}

Fields

tag

The tag of the dns server.

address

==Required==

The address of the dns server.

Protocol	Format
System	local
TCP	tcp://1.0.0.1
UDP	8.8.8.8 udp://8.8.4.4
TLS	tls://dns.google
HTTPS	https://1.1.1.1/dns-query
QUIC	quic://dns.adguard.com
HTTP3	h3://8.8.8.8/dns-query
RCode	rcode://refused
DHCP	dhcp://auto or dhcp://en0
FakeIP	fakeip

!!! warning ""

To ensure that Android system DNS is in effect, rather than Go's built-in default resolver, enable CGO at compile time.

!!! info ""

the RCode transport is often used to block queries. Use with rules and the `disable_cache` rule option.

| RCode | Description | |-------------------|-----------------------| | success | No error | | format_error | Format error | | server_failure | Server failure | | name_error | Non-existent domain | | not_implemented | Not implemented | | refused | Query refused |

address_resolver

==Required if address contains domain==

Tag of a another server to resolve the domain name in the address.

address_strategy

The domain strategy for resolving the domain name in the address.

One of prefer_ipv4 prefer_ipv6 ipv4_only ipv6_only.

dns.strategy will be used if empty.

strategy

Default domain strategy for resolving the domain names.

One of prefer_ipv4 prefer_ipv6 ipv4_only ipv6_only.

Take no effect if overridden by other settings.

detour

Tag of an outbound for connecting to the dns server.

Default outbound will be used if empty.

client_subnet

!!! question "Since sing-box 1.9.0"

Append a edns0-subnet OPT extra record with the specified IP prefix to every query by default.

If value is an IP address instead of prefix, /32 or /128 will be appended automatically.

Can be overrides by rules.[].client_subnet.

Will overrides dns.client_subnet.