# Node.js - Node-RED v3.0.2 MQTT Configuration Windows Quirk

**URL:** <https://discourse.nodered.org/t/node-js-node-red-v3-0-2-mqtt-configuration-windows-quirk/77354>\
**Category:** General\
**Created:** [7 April 2023 21:07 UTC](https://discourse.nodered.org/t/node-js-node-red-v3-0-2-mqtt-configuration-windows-quirk/77354 "2023-04-07T21:07:33Z")\
**Posts on this page:** 10\
**Page:** 2

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**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [9 April 2023 21:48 UTC](https://discourse.nodered.org/t/node-js-node-red-v3-0-2-mqtt-configuration-windows-quirk/77354/21 "2023-04-09T21:48:01Z")

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It’s probably related to this change in nodejs behaviour from v17 onwards

> <https://github.com/nodejs/node/issues/40537>
>
> \### Version
> 
> v17.0.0
> 
> \### Platform
> 
> Darwin pink.local 20.6.0 Darwin Kernel Versi…on 20.6.0: Mon Aug 30 06:12:21 PDT 2021; root:xnu-7195.141.6~3/RELEASE\_X86\_64 x86\_64
> 
> \### Subsystem
> 
> \_No response\_
> 
> \### What steps will reproduce the bug?
> 
> \`\`\`js
> var http = require('http')
> var server = http.createServer(function (req, res) { /\* ... \*/ })
> server.listen(3000, 'localhost', function (\_err) { 
> console.log('server listening: %s', server.address())
> })
> \`\`\`
> 
> I'm not sure what the underlying mechanism is, but it looks to me like the resolution of "localhost" for \`server.listen(PORT, HOST, ...)\` and for \`http.request('http://localhost/...', ...)\` changed from favouring IPv4 in node v16 and earlier, to favouring IPv6. The result is some possibly confusing breakages when using IPv4 values such as \`127.0.0.1\` and \`0.0.0.0\`. For example, the following script errors with node v17, but succeeds with node v16:
> 
> \`\`\`js
> // example-localhost-means-which-ipv.js
> var http = require('http')
> 
> var server = http.createServer(function (req, res) {
> req.on('data', function (chunk) {
> console.log('server req data: %s', chunk)
> })
> req.on('end', function () {
> console.log('server req end')
> res.end('pong')
> })
> })
> 
> // Listen on IPv4 address.
> var theHost = '127.0.0.1'
> server.listen(3000, theHost, function (\_err) {
> console.log('server listening: %s', server.address())
> 
> // GET from localhost.
> var theUrl = 'http://localhost:3000/ping'
> console.log('client req: GET %s', theUrl)
> http.get(theUrl, function (res) {
> console.log('client res:', res.statusCode, res.headers)
> res.on('data', (chunk) =\> {
> console.log('client data: %s', chunk)
> })
> res.on('end', () =\> {
> console.log('client end')
> server.close()
> })
> })
> })
> \`\`\`
> 
> \`\`\`
> % node --version
> v17.0.0
> 
> % node example-localhost-means-which-ipv.js
> server listening: { address: '127.0.0.1', family: 'IPv4', port: 3000 }
> client req: GET http://localhost:3000/ping
> node:events:368
> throw er; // Unhandled 'error' event
> ^
> 
> Error: connect ECONNREFUSED ::1:3000
> at TCPConnectWrap.afterConnect \[as oncomplete\] (node:net:1161:16)
> Emitted 'error' event on ClientRequest instance at:
> at Socket.socketErrorListener (node:\_http\_client:447:9)
> at Socket.emit (node:events:390:28)
> at emitErrorNT (node:internal/streams/destroy:164:8)
> at emitErrorCloseNT (node:internal/streams/destroy:129:3)
> at processTicksAndRejections (node:internal/process/task\_queues:83:21) {
> errno: -61,
> code: 'ECONNREFUSED',
> syscall: 'connect',
> address: '::1',
> port: 3000
> }
> 
> Node.js v17.0.0
> 
> % nvm use 16
> Now using node v16.11.1 (npm v8.0.0)
> 
> % node example-localhost-means-which-ipv.js
> server listening: { address: '127.0.0.1', family: 'IPv4', port: 3000 }
> client req: GET http://localhost:3000/ping
> server req end
> client res: 200 {
> date: 'Wed, 20 Oct 2021 21:01:56 GMT',
> connection: 'close',
> 'content-length': '4'
> }
> client data: pong
> client end
> \`\`\`
> 
> Similarly, if we reverse things to listen on \`'localhost'\` and GET from \`'http://\[::1\]:3000/ping'\` (IPv6), then it fails on node v16 and passes on node v17. 
> 
> As I said above, I don't know the mechanism for selecting IPv4 or IPv6. I suspect this isn't a "bug", except perhaps a lack of documentation? I don't see any mention of localhost of IPv6 in the changelog. Thanks.
> 
> 
> 
> \### How often does it reproduce? Is there a required condition?
> 
> Everytime. While I tested mostly on macOS, I believe I was seeing this in GitHub Action tests running on linux containers.
> 
> \### What is the expected behavior?
> 
> \_No response\_
> 
> \### What do you see instead?
> 
> \_No response\_
> 
> \### Additional information
> 
> \_No response\_

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<div class="post-metadata">

**Author:** ![tree-frog](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/tree-frog/32/89303_2.png) [@tree-frog](https://discourse.nodered.org/u/tree-frog)\
**Post date:** [10 April 2023 02:46 UTC](https://discourse.nodered.org/t/node-js-node-red-v3-0-2-mqtt-configuration-windows-quirk/77354/22 "2023-04-10T02:46:50Z")

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Mosquitto Broker. That version has not been updated either. At this time I would need to get the version number.

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**Author:** ![tree-frog](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/tree-frog/32/89303_2.png) [@tree-frog](https://discourse.nodered.org/u/tree-frog)\
**Post date:** [10 April 2023 03:23 UTC](https://discourse.nodered.org/t/node-js-node-red-v3-0-2-mqtt-configuration-windows-quirk/77354/23 "2023-04-10T03:23:07Z")

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> [@TotallyInformation](#):
>
> I'm not entirely sure I understood the original question. But in case it helps, you cannot make assumptions about how "localhost" is represented when trying to account for it in Node.JS.

Why does the MQTT node need different syntax for the address and does not allow "localhost" ? That's the "op's" "oq".

Steve, Sorry for not answering your question about Mosquitto. I guess I just did not see it.  
op = Original Post  
oq = Original Question

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**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [10 April 2023 10:15 UTC](https://discourse.nodered.org/t/node-js-node-red-v3-0-2-mqtt-configuration-windows-quirk/77354/24 "2023-04-10T10:15:42Z")

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> [@tree-frog](#):
>
> Why does the MQTT node need different syntax for the address and does not allow "localhost" ?

What I was trying to say is that while localhost is certainly accepted as valid by the node, there are several factors as to why "localhost" the concept may have several different actual values depending on use, host file, DNS, DHCP and such settings. Doesn't really help you get an answer but helps understand the context.

Indeed, I think I left `0.0.0.0` off the list as well which may also be valid (representing all of the possible IPv4 addresses across all local interfaces).

If you wanted to, you could probably adjust `C:\Windows\System32\drivers\etc\hosts` to deal with the issue. Though Windows tells you that localhost resolution is handled by DNS. But on my desktop, I have `127.0.0.1 kubernetes.docker.internal` as a line in my hosts file which was added by Docker Desktop for Windows.

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [10 April 2023 10:36 UTC](https://discourse.nodered.org/t/node-js-node-red-v3-0-2-mqtt-configuration-windows-quirk/77354/25 "2023-04-10T10:36:16Z")

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@TotallyInformation, I believe the fundamental problem here is that the connection to mosquitto fails if ipv6 is used. Do you know whether the default mosquitto install on Windows prevents IPv6? Looking at [the docs](https://mosquitto.org/man/mosquitto-conf-5.html) it appears that, to disable ipv6, the mosquitto conf file would have to contain `socket_domain ipv4`. If there is no `socket_domain` setting in the config file then mosquitto will listen on both.

@tree-frog how did you install mosquitto, and have you made any changes to the config files?

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**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [10 April 2023 11:01 UTC](https://discourse.nodered.org/t/node-js-node-red-v3-0-2-mqtt-configuration-windows-quirk/77354/26 "2023-04-10T11:01:10Z")

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> [@Colin](#):
>
> I believe the fundamental problem here is that the connection to mosquitto fails if ipv6 is used. Do you know whether the default mosquitto install on Windows prevents IPv6? Looking at [the docs](https://mosquitto.org/man/mosquitto-conf-5.html) it appears that, to disable ipv6, the mosquitto conf file would have to contain `socket_domain ipv4`. If there is no `socket_domain` setting in the config file then mosquitto will listen on both.

Honestly, I've not tried. I don't run Mosquitto on Windows because I only use it for work, development, entertainment, .... 😁 Like most people, I have a small server that runs ... well, servers.

Did you say how you have your listener configured in Mosquitto?

* * *

> `socket_domain` [ipv4 | ipv6]
> 
> By default, a listener will attempt to listen on all supported IP protocol versions. If you do not have an IPv4 or IPv6 interface you may wish to disable support for either of those protocol versions. In particular, note that due to the limitations of the websockets library, it will only ever attempt to open IPv6 sockets if IPv6 support is compiled in, and so will fail if IPv6 is not available.
> 
> Set to `ipv4` to force the listener to only use IPv4, or set to `ipv6` to force the listener to only use IPv6. If you want support for both IPv4 and IPv6, then do not use the `socket_domain` option.
> 
> Not reloaded on reload signal.

Note the comment about the websockets library. Not sure if that applies here. However, I note that the mosquitto log should say which interfaces were activated and will say whether the ip4/ip6 versions were used.

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [10 April 2023 12:20 UTC](https://discourse.nodered.org/t/node-js-node-red-v3-0-2-mqtt-configuration-windows-quirk/77354/27 "2023-04-10T12:20:24Z")

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> [@TotallyInformation](#):
>
> I don't run Mosquitto on Windows

Sorry, I thought that you did run such things on Windows.

> [@TotallyInformation](#):
>
> Did you say how you have your listener configured in Mosquitto?

it isn't me that has the problem, I don't run windows at all (except for Fusion 360 in a VM). I am trying to understand why the OP has the problem, so that we will know the answer next time it comes up.

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**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [10 April 2023 13:37 UTC](https://discourse.nodered.org/t/node-js-node-red-v3-0-2-mqtt-configuration-windows-quirk/77354/28 "2023-04-10T13:37:46Z")

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> [@Colin](#):
>
> Sorry, I thought that you did run such things on Windows.

Not a problem. I _have_ run Mosquitto and InfluxDB/Grafana on Windows but honestly, I think we can all agree that Windows is much better as a desktop OS than a server! 😁 I'm too used to the Windows way of doing things to be comfortable switching even though I do have both MacOS and Linux to hand if needed. Having started in the IBM world \>40yrs ago and coming up through OS/2 and every version of LAN Manager and Windows, it is a hard habit to break.

But even so, I only use Windows for my daily-driver workstation and laptops. For servers, I use Linux and have done for many years. Debian is my server OS of choice.

> [@Colin](#):
>
> it isn't me that has the problem

Wasn't aimed at you, I probably selected the wrong previous post.

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**Author:** ![tree-frog](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/tree-frog/32/89303_2.png) [@tree-frog](https://discourse.nodered.org/u/tree-frog)\
**Post date:** [12 April 2023 21:01 UTC](https://discourse.nodered.org/t/node-js-node-red-v3-0-2-mqtt-configuration-windows-quirk/77354/29 "2023-04-12T21:01:41Z")

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Colin,

It appears to me that this is in concert with Node.js, Mosquitto MQTT and Windows as it is configured as well. I "usually" have IPv6 disabled on these machines. But not always. I realize there are things at play on my settings and configuration side that I'll need to verify. Thank you very much for looking into this. I'll have more time next week to look at the details on my configuration on Mosquitto and then the IPv6 configuration on that Windows 10 PC.

I have a path forward at present to rename the localhost tag to 127.0.0.1 which is acceptable for now. Please note that this caused issues on upgrade and porting code which I did have to puzzle through how to get it working. I believe this should be understood and I will certainly assist you as much as possible and time permitting.

Kind Regards,

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [26 April 2023 21:01 UTC](https://discourse.nodered.org/t/node-js-node-red-v3-0-2-mqtt-configuration-windows-quirk/77354/30 "2023-04-26T21:01:45Z")

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