Fix windows DNS server resolution

[greguintow]

Summary

This PR addresses a Windows DNS regression observed after the c-ares update in the following nodejs versions:

• Node.js >= 20.20.0
• Node.js >= 22.22.0
• Node.js >= 24.13.0
• Node.js >= 25.3.0

Where I first realized when trying to connect to MongoDB atlas through VPN in Windows failed.

• Restore Windows DNS resolver server ordering parity with the previous version for this setup:
  • before fix (regressed): ['127.0.0.1']
  • after fix: ['::ffff:127.0.2.2', '::ffff:127.0.2.3', '127.0.2.2', '127.0.2.3']
• Keep discovered DNS servers even if Windows suffix parsing fails, preventing
  fallback to loopback-only resolver configuration
• Windows DNS discovery behavior in get_DNS_Windows() (e.g. GetNetworkParams,
  ordering) as needed for this setup

I believe it was regressed after the c-ares update to v1.34.6:

• deps: update c-ares to v1.34.6 #60997

Testing

Windows validation performed with:

./vcbuild.bat release openssl-no-asm
./Release/node.exe -e "console.log(require('node:dns').getServers())"

Observed results:

• dns.getServers() now returns:
  ['::ffff:127.0.2.2', '::ffff:127.0.2.3', '127.0.2.2', '127.0.2.3'] just like was before the regression
• Successfully connects to MongoDB Atlas through VPN with mongodb+srv://

It could also be tested with switching between 24.12 to 24.13 and observing the DNS servers.

Notes

Ideally, the fix would be backdated for all the affected versions (v20, v22, v24, v25)

Thank you for your time and consideration on looking into this 🙏.

[nodejs-github-bot]

Review requested:

• @nodejs/net
• @nodejs/security-wg

[ProKashif]

Good job

[MrMuhammadAbdullah1704]

Its definitly going to help me bypass this annoying issue. Would love to see it merged

[greguintow]

@anonrig could you help review this PR please if you have the chance?

[greguintow]

could you help review as well please? @mcollina @pimterry @trivikr @Ethan-Arrowood @RafaelGSS @lpinca @cjihrig @richardlau @juanarbol @marco-ippolito

[anonrig]

@anonrig could you help review this PR please if you have the chance?

Please add a test.

[anonrig]

Also this change needs to be upstreamed. You're updating deps/cares folder which will get overwritten whenever we update cares.

[greguintow]

Also this change needs to be upstreamed. You're updating deps/cares folder which will get overwritten whenever we update cares.

Hey @anonrig , thanks for the direction on this! It seems like it was already fixed on c-ares end 2 weeks ago, asked them here if there any soon plans to release, once it's released, I believe nodejs bot would raise a PR updating the lib shortly after.

I believe this PR won't be needed in this case, closing it for now.

Thanks for everything!