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The dns module enables name resolution. For example, use it to look up IP addresses of host names.
Syntax
The syntax for including the DNS module in your application:
var dns = require('dns');
DNS Methods
Let’s see a list of commonly used DNS methods:
| Method | Description |
|---|---|
| getServers() | Returns an array containing all IP addresses belonging to the current server |
| lookup() | Looks up a hostname. A callback function contains information about the hostname, including it’s IP address |
| lookupService() | Looks up a address and port. A callback function contains information about the address, such as the hostname |
| resolve() | Returns an array of record types belonging to the specified hostname |
| resolve4() | Looks up an IPv4 address. The callback function includes an array of IPv4 addresses |
| resolve6() | Looks up an IPv6 address. The callback function includes an array of IPv6 addresses |
| resolveCname() | Looks up CNAME records for the specified hostname. The callback function includes an array of available domains for the hostname |
| resolveMx() | Looks up mail exchange records for the specified hostname. |
| resolveNaptr() | Looks up regular expression based records for the specified hostname. |
| resolveNs() | Looks up name server records for the specified hostname. |
| resolveSoa() | Looks up a start of authority record for the specified hostname. |
| resolveSrv() | Looks up service records for the specified hostname. |
| resolvePtr() | Looks up pointer records for the specified hostname. |
| resolveTxt() | Looks up text query records for the specified hostname. |
| reverse() | Reverses an IP address into an array of hostnames |
| setServers() | Sets the IP addresses of the servers |
Examples
const dns = require('dns');
dns.lookup('www.google.com', (err, addresses, family) => {
console.log('addresses:', addresses);
});
var dns = require('dns');
var demo = dns.lookupService('127.0.0.1', 21, (err, hostname, service) => {
console.log(hostname, service);
});
const dns = require('dns');
const rrtype="A";
dns.resolve('www.google.com', rrtype, (err,
records) => console.log('records: %j', records));
const rrtype1="TXT";
dns.resolve('www.google.com', rrtype1, (err,
records) => console.log('records: %j', records));
const rrtype2="NS";
dns.resolve('www.google.com', rrtype2, (err,
records) => console.log('records: %j', records));