Usage in Deno
import * as mod from "node:dns";
The node:dns module enables name resolution. For example, use it to look up IP
addresses of host names.
Although named for the Domain Name System (DNS), it does not always use the DNS protocol for lookups. lookup uses the operating system facilities to perform name resolution. It may not need to perform any network communication. To perform name resolution the way other applications on the same system do, use lookup.
import dns from 'node:dns';
dns.lookup('example.org', (err, address, family) => {
console.log('address: %j family: IPv%s', address, family);
});
// address: "93.184.216.34" family: IPv4
All other functions in the node:dns module connect to an actual DNS server to
perform name resolution. They will always use the network to perform DNS
queries. These functions do not use the same set of configuration files used by lookup (e.g. /etc/hosts). Use these functions to always perform
DNS queries, bypassing other name-resolution facilities.
import dns from 'node:dns';
dns.resolve4('archive.org', (err, addresses) => {
if (err) throw err;
console.log(`addresses: ${JSON.stringify(addresses)}`);
addresses.forEach((a) => {
dns.reverse(a, (err, hostnames) => {
if (err) {
throw err;
}
console.log(`reverse for ${a}: ${JSON.stringify(hostnames)}`);
});
});
});
See the Implementation considerations section for more information.
Get the default value for order in lookup and dnsPromises.lookup().
The value could be:
Returns an array of IP address strings, formatted according to RFC 5952, that are currently configured for DNS resolution. A string will include a port section if a custom port is used.
Resolves a host name (e.g. 'nodejs.org') into the first found A (IPv4) or
AAAA (IPv6) record. All option properties are optional. If options is an
integer, then it must be 4 or 6 – if options is 0 or not provided, then
IPv4 and IPv6 addresses are both returned if found.
Resolves the given address and port into a host name and service using
the operating system's underlying getnameinfo implementation.
Get the default value for verbatim in lookup and dnsPromises.lookup().
The value could be:
Returns an array of IP address strings, formatted according to RFC 5952, that are currently configured for DNS resolution. A string will include a port section if a custom port is used.
Resolves a host name (e.g. 'nodejs.org') into the first found A (IPv4) or
AAAA (IPv6) record. All option properties are optional. If options is an
integer, then it must be 4 or 6 – if options is not provided, then IPv4
and IPv6 addresses are both returned if found.
Resolves the given address and port into a host name and service using
the operating system's underlying getnameinfo implementation.
Uses the DNS protocol to resolve a host name (e.g. 'nodejs.org') into an array
of the resource records. When successful, the Promise is resolved with an
array of resource records. The type and structure of individual results vary
based on rrtype:
Uses the DNS protocol to resolve IPv4 addresses (A records) for the hostname. On success, the Promise is resolved with an array of IPv4
addresses (e.g. ['74.125.79.104', '74.125.79.105', '74.125.79.106']).
Uses the DNS protocol to resolve IPv6 addresses (AAAA records) for the hostname. On success, the Promise is resolved with an array of IPv6
addresses.
Uses the DNS protocol to resolve all records (also known as ANY or * query).
On success, the Promise is resolved with an array containing various types of
records. Each object has a property type that indicates the type of the
current record. And depending on the type, additional properties will be
present on the object:
Uses the DNS protocol to resolve CAA records for the hostname. On success,
the Promise is resolved with an array of objects containing available
certification authority authorization records available for the hostname (e.g. [{critical: 0, iodef: 'mailto:pki@example.com'},{critical: 128, issue: 'pki.example.com'}]).
Uses the DNS protocol to resolve CNAME records for the hostname. On success,
the Promise is resolved with an array of canonical name records available for
the hostname (e.g. ['bar.example.com']).
Uses the DNS protocol to resolve mail exchange records (MX records) for the hostname. On success, the Promise is resolved with an array of objects
containing both a priority and exchange property (e.g.[{priority: 10, exchange: 'mx.example.com'}, ...]).
Uses the DNS protocol to resolve regular expression-based records (NAPTR records) for the hostname. On success, the Promise is resolved with an array
of objects with the following properties:
Uses the DNS protocol to resolve name server records (NS records) for the hostname. On success, the Promise is resolved with an array of name server
records available for hostname (e.g.['ns1.example.com', 'ns2.example.com']).
Uses the DNS protocol to resolve pointer records (PTR records) for the hostname. On success, the Promise is resolved with an array of strings
containing the reply records.
Uses the DNS protocol to resolve a start of authority record (SOA record) for
the hostname. On success, the Promise is resolved with an object with the
following properties:
Uses the DNS protocol to resolve service records (SRV records) for the hostname. On success, the Promise is resolved with an array of objects with
the following properties:
Uses the DNS protocol to resolve text queries (TXT records) for the hostname. On success, the Promise is resolved with a two-dimensional array
of the text records available for hostname (e.g.[ ['v=spf1 ip4:0.0.0.0 ', '~all' ] ]). Each sub-array contains TXT chunks of
one record. Depending on the use case, these could be either joined together or
treated separately.
Performs a reverse DNS query that resolves an IPv4 or IPv6 address to an array of host names.
Set the default value of order in dns.lookup() and [lookup](.././dns/~/lookup). The value could be:
Sets the IP address and port of servers to be used when performing DNS
resolution. The servers argument is an array of RFC 5952 formatted
addresses. If the port is the IANA default DNS port (53) it can be omitted.
Performs a reverse DNS query that resolves an IPv4 or IPv6 address to an array of host names.
Set the default value of order in lookup and dnsPromises.lookup().
The value could be:
Sets the IP address and port of servers to be used when performing DNS
resolution. The servers argument is an array of RFC 5952 formatted
addresses. If the port is the IANA default DNS port (53) it can be omitted.
The dns.promises API provides an alternative set of asynchronous DNS methods
that return Promise objects rather than using callbacks. The API is accessible
via import { promises as dnsPromises } from 'node:dns' or import dnsPromises from 'node:dns/promises'.
Limits returned address types to the types of non-loopback addresses configured on the system. For example, IPv4 addresses are only returned if the current system has at least one IPv4 address configured.
If dns.V4MAPPED is specified, return resolved IPv6 addresses as
well as IPv4 mapped IPv6 addresses.
If the IPv6 family was specified, but no IPv6 addresses were found, then return IPv4 mapped IPv6 addresses. It is not supported on some operating systems (e.g. FreeBSD 10.1).