dns.resolve throws ETIMEOUT for custom dns server

[zombieleet]

Version

v18.17.0

Platform

Darwin MacBook-Pro.local 22.6.0 Darwin Kernel Version 22.6.0: Wed Jul 5 22:21:53 PDT 2023; root:xnu-8796.141.3~6/RELEASE_ARM64_T6020 arm64

Subsystem

dns, cares_wrap?

What steps will reproduce the bug?

dns.resolve was able to communciate to the custom dns server, but dns.resolve timesout before it receives a response from the custom dns server.

const dgram = require('node:dgram')
const dns = require('node:dns/promises')

// to encode and decode dns message
const dnsPacket = require('dns-packet')

const dgramSocket = dgram.createSocket('udp4').bind(53)


dgramSocket.on('listening', () => {
  const address = dgramSocket.address();
  console.log('listening on ', address.address, address.port);
});

dgramSocket.on('message', (packet,remoteInfo) => {
   const query = dnsPacket.decode(packet);
   const question = query.questions[0];

   const dnsAnswer = {
       type: 'response',
       id: query.id,
       flags: dnsPacket.AUTHORITATIVE_ANSWER,
       questions: query.questions,
       answers: [
          {
            type: question.type,
            class: 'IN',
            name: question.name,
            ttl: 300,
            // googles ipv4 address
            data: '172.217.16.174',
           },
         ],
       };

      const dnsAnswerBuffer = dnsPacket.encode(dnsAnswer);

      dgramSocket.send(dnsAnswerBuffer, remoteInfo.port, remoteInfo.address, (err, s) => {
          console.log({ err, s });
      });
});

;( async () => {
  const myResolver = new dns.Resolver();
  myResolver.setServers([ '0.0.0.0:53' ])
  // this throws ETIMEDOUT
  console.log(await myResolver.resolve('fake-address.com', 'A'))
})();

How often does it reproduce? Is there a required condition?

It will always throw an ETIMEOUT, at first I thought it was an issue with dns-packet , so I tried with other dns payload parsing libraries but dns.resolve still does not receive response from the custom dns server.

What is the expected behavior? Why is that the expected behavior?

The expected behavior is for dns.resolve to respond with the fake dns information sent by the custom dns server.

What do you see instead?

dns.resolve throws ETIMEOUT after 4 retries (this is the default retry set in node core).

Additional information

No response

[bnoordhuis]

Converted to a discussion because it falls short as a bug report. You need to conclusively demonstrate that the bug is with node and not somewhere else (your system, that third-party library, etc.)

[zombieleet]

Hello @bnoordhuis thanks for your reply.

I also tried the same example with the dig command, I was able to get a response back from the custom dns server.

The only thing that changed in the below code is the use of dns.resolve

const dgram = require('node:dgram')
const dns = require('node:dns/promises')

// to encode and decode dns message
const dnsPacket = require('dns-packet')

const dgramSocket = dgram.createSocket('udp4').bind(53)


dgramSocket.on('listening', () => {
  const address = dgramSocket.address();
  console.log('listening on ', address.address, address.port);
});

dgramSocket.on('message', (packet,remoteInfo) => {
   const query = dnsPacket.decode(packet);
   const question = query.questions[0];

   const dnsAnswer = {
       type: 'response',
       id: query.id,
       flags: dnsPacket.AUTHORITATIVE_ANSWER,
       questions: query.questions,
       answers: [
          {
            type: question.type,
            class: 'IN',
            name: question.name,
            ttl: 300,
            // googles ipv4 address
            data: '172.217.16.174',
           },
         ],
       };

      const dnsAnswerBuffer = dnsPacket.encode(dnsAnswer);

      dgramSocket.send(dnsAnswerBuffer, remoteInfo.port, remoteInfo.address, (err, s) => {
          console.log({ err, s });
      });
});

dig @0.0.0.0 fake-address.com

I get this response back

; <<>> DiG 9.10.6 <<>> @0.0.0.0 fake-address.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42310
;; flags: qr aa; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;fake-address.com.		IN	A

;; ANSWER SECTION:
fake-address.com.	300	IN	A	172.217.16.174

;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(0.0.0.0)
;; WHEN: Sun Sep 24 16:30:51 WAT 2023
;; MSG SIZE  rcvd: 66

[zombieleet]

I also decided to use a third-party package for resolving dns node-dns2

dgram udp socket

const dgram = require('node:dgram')
const dns = require('node:dns/promises')
const utils = require('node:util');
// to encode and decode dns message
const dnsPacket = require('dns-packet')

const dgramSocket = dgram.createSocket('udp4').bind(53)


dgramSocket.on('listening', () => {
  const address = dgramSocket.address();
  console.log('listening on ', address.address, address.port);
});

dgramSocket.on('message', (packet,remoteInfo) => {
   const query = dnsPacket.decode(packet);
   const question = query.questions[0];

   const dnsAnswer = {
       type: 'response',
       id: query.id,
       flags: dnsPacket.AUTHORITATIVE_ANSWER,
       questions: query.questions,
       answers: [
          {
            type: question.type,
            class: 'IN',
            name: question.name,
            ttl: 300,
            // googles ipv4 address
            data: '172.217.16.174',
           },
         ],
       };

      const dnsAnswerBuffer = dnsPacket.encode(dnsAnswer);

      dgramSocket.send(dnsAnswerBuffer, remoteInfo.port, remoteInfo.address, (err, s) => {
          console.log({ err, s });
      });
});

node-dns dns client

const DNS = require('dns2');

const dns = new DNS({ nameServers: [ '0.0.0.0' ], resolverProtocol: 'UDP', port: 53 })

;( async () => {
  console.log(await dns.resolveA('google.com'))
})()