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Why listening "::" (all IPv6) also get "0.0.0.0"(all IPv4) listened? #9390
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Or maybe this is just a trick implementation of the Windows OS itself ?
It's called dual-stack mode and it's platform-specific. Linux lets you enable/disable it through the net.ipv6.bindv6only sysctl, I assume Windows has something similar.
I'll add doc tags because it doesn't look like the documentation currently mentions this. Libuv has UV_TCP_IPV6ONLY and UV_UDP_IPV6ONLY flags that we could leverage along the lines of
net.createServer({ ipv6only: true }).Reacted by Jiawen GengThank you. You saved my time.
This dual stack mode is certainly confusing, as most people would expect
::(The alias for all v6 addresses) to bind to just v6, not magically also binding v4 on certain platforms.The user has no way of knowing if the platform supports dual-stack, so if one wants to listen on v4 and v6, you'd have to try listening on both
::and0.0.0.0and catch theEADDRINUSEfrom the v4listenon platforms that don't support it (I think macOS is an example).I'd argue that
ipv6onlybehavior should be made the default behaviour whenhostnameis::. The dual-stack mode could still be in effect whenhostnameisundefined.Reacted by amauri, Jens Habegger, Mika Fischer, Andrew Stiegmann, Christian Barcenas and Kip ObenaufReacted by Joe BowbeerTwo things to note about this bug:
- It makes it more difficult than necessary to create portable code.
- It makes it impossible to create a IPv6-only socket with nodejs on Linux, and that just seems wrong.
Hi, i forgot to tell everyone that this phenomenon
not only happens in Windows, but also Linux, Mac.As my test,
On Mac (OS X EI Captitan 10.11.6), the
netstatdoes showstcp46which means TCP4 and TCP6.tcp46 0 0 *.5555 *.* LISTENOn Linux Ubuntu 16.04, the
netstatdoes show only tcp6, but in fact, the same TCP4 port can be connected!tcp6 0 0 :::5555 :::* LISTENAfter all, this is very OS-dependent.
Reacted by Jim Montgomery and Sunny Bean5 remaining items
How do I calculate
THE_EQUIVALENT_IPv4_ADDR? I run linux, andnode -e "net.createServer(c=>console.log).listen(5555,'fe80::7d2b:81c4:1f2:2ad%wlan1')"worked fine.@sam-github thank you for the test. I just run
ip addr | grep inetto show all ip4 ip6 pair and find it manually.Not sure this is what you want, or if my machine has enough support for IPv6, but here it is:
% ip addr | grep inet inet 127.0.0.1/8 scope host lo inet6 ::1/128 scope host inet 192.168.0.181/24 brd 192.168.0.255 scope global dynamic wlan1 inet6 fe80::7d2b:81c4:1f2:2ad/64 scope link % node -e "require('net').createServer(c=>console.log).listen(5555,'fe80::7d2b:81c4:1f2:2ad%wlan1')" % node -e "net.connect(5555,'192.168.0.181',()=>console.log('connected'))" events.js:161 throw er; // Unhandled 'error' event ^ Error: connect ECONNREFUSED 192.168.0.181:5555@sam-github thank you.
This is what i want! This is a proof of that "On linux, without special configuration, listening actual IPv6 address will not cause equivalent IPv4 address also being listened"
So, what is your linux distribution? (
cat /etc/*release*can see it)ubuntu 16.10, kernel 4.8.0-34-generic
I think it likely proves just "on this linux distro, with default configuration...", I could probably config ipv4 to redirect to ipv6
Yes, with default configuration, this is exactly what i want to prove.
Thank you.
So, all typical test are done.
OS Listen IPv6 address Does equivalent IPv4 auto listened Windows 7Pro/10 :: YES Mac OS X EI Capitan 10.11.6 :: YES Ubuntu 14.04/16.04 :: YES Windows 7Pro/10 ::1 NO Mac OS X EI Capitan 10.11.6 ::1 NO Ubuntu 14.04/16.04 ::1 NO Windows 7Pro/10 ActualIPv6Address NO Mac OS X EI Capitan 10.11.6 ActualIPv6Address NO Ubuntu 16.10 ActualIPv6Address NO All test is done under default configuration about IPv6.
So my conclusion is that we should only mention about the amazing effect of listening
::.Reacted by Bilge, Sunny Bean and Guillaume Raffin- added 2 commits that reference this issue
on Feb 20, 2017 - added a commit that references this issue
on Jul 27, 2026
I found a strange problem, i created a simple TCP server to listen at port 5555 of "::"(all IPv6 interfaces)
Then i found all IPv4 interfaces are also listening port 5555.
Another relevant problem is, if i do not specify host, or use
undefined, or empty string,It should listen :: OR 0.0.0.0, not both, according the document:
But the fact is both :: and 0.0.0.0 get listened.
I don't know which is correct? document or implementation? Anyway, this is a bit confusing.
Or maybe this is just a trick implementation of the Windows OS itself ?