Question: does dns.resolveMx support unicode domains?

[WesTyler]

• Version: v6.9.0
• Platform: 16.3.0 Darwin Kernel Version 16.3.0: Thu Nov 17 20:23:58 PST 2016; root:xnu-3789.31.2~1/RELEASE_X86_64 x86_64
• Subsystem: DNS

According to this article, the domain 域通联达。在线 should return a valid MX record. But calling dns.resolveMX returns an error:

dns.resolveMx('域通联达。在线', (err, record) => {console.log(err); console.log(record);})
QueryReqWrap {
  bindingName: 'queryMx',
  callback: { [Function: asyncCallback] immediately: true },
  hostname: '域通联达。在线',
  oncomplete: [Function: onresolve],
  domain:
   Domain {
     domain: null,
     _events: { error: [Function] },
     _eventsCount: 1,
     _maxListeners: undefined,
     members: [] } }
> { Error: queryMx ENOTFOUND 域通联达。在线
    at errnoException (dns.js:28:10)
    at QueryReqWrap.onresolve [as oncomplete] (dns.js:216:19)
  code: 'ENOTFOUND',
  errno: 'ENOTFOUND',
  syscall: 'queryMx',
  hostname: '域通联达。在线' }
undefined

If this is not an issue within the dns api but with that specific domain, can you point me to an international domain for which the .resolveMX call is working?

[bnoordhuis]

You need two additional steps. This should work:

const dns = require('dns');
const punycode = require('punycode');

const domain = '域通联达。在线';

dns.resolveMx(punycode.toASCII(domain.replace(/。/, '.')), (err, res) => {
  if (err) throw err;
  console.log(res);
});

However, this particular domain doesn't appear to have MX records. It does have an A record though; dns.resolve(...) prints a result.

[WesTyler]

Ah, ok. I was hoping punycoding wouldn't be necessary. Thanks very much, that's what I was needing to know!