[windows]dgram socket not receiving on network without internet connection

[farfromrefug]

I have a server running on a raspberry PI.
that server regularly broadcast over all its interfaces.
that server also publish an adhoc network using hostapd

Now i have clients apps on Windows/Macos that should receive the broadcast using dgram sockets.
Everything works perfectly on macos.
On windows in works when both are the same network with internet connection.

Now when the windows client (windows 10, nodejs 8.6.0) is connected to the Pi Adhoc network the dgram socket does not see the messages. It binds correctly but that s it.
I know this issue is within nodejs because wireshark correctly sees the UDP packets and everything is good.

The client code is as simple as this:

const dgram = require('dgram');
const socket = dgram.createSocket({
    type:'udp4',
    reuseAddr: true
});

socket.on("message", (msg, rinfo) => {
   console.log('message', msg, rinfo);
}).on("listening", () => {
    // console.log('udp listening');
    // this.sockets[interName] = socket;
    console.log('udp listening', socket.address());
}).on("error", (err) => {
    console.log('udp error', err);
}).on("close", () => {
    console.log('udp close', err);

});
console.log('bind', 2900, '0.0.0.0');
socket.bind(2900, '0.0.0.0');

I am not sure it s related to internet but that's the only thing i see.
I tried with a custom lookup method too but it does not seem to change anything.

Any help would be appreciated.

Thanks

[bnoordhuis]

I know this issue is within nodejs because wireshark correctly sees the UDP packets and everything is good.

Can you expand? Post wireshark or tcpdump output if you have it.

[farfromrefug]

@bnoordhuis sure will do this. Can't do it before monday though

[bzoz]

Of the top of my head, two issues could be related: #14900 and #17641 (which is fixed on master)

[farfromrefug]

@bzoz about the first one. I don't if it's relevant but i do get the "listening" event, but no message after that. Also binding to '0.0.0.0' does work when the network as internet connection

[farfromrefug]

Here is the export wireshark report.
Is that what you want? or do you prefer another format?
udp-error.zip

[bnoordhuis]

I see PONG datagrams being broadcasted from 192.138.143.1:2900 to 192.138.143.255:2900 that advertise something about port 7265. If this...

I know this issue is within nodejs because wireshark correctly sees the UDP packets and everything is good.

...means wireshark receives packets while node.js does not (on the same machine), then you probably have a firewall or routing rule that drops the packets, or something to that effect.

Tools like wireshark and tcpdump are not affected by that because they run very early in the filter chain and they put the interface into promiscuous mode so they can capture all network traffic, not just deliverable traffic.

Since I don't see anything that indicates a node.js bug I'm going to close this out but if you have evidence to the contrary (say, a python script that works where node.js does not), then please post it.

If you have follow-up questions, then by all means post them to the help repo. Cheers.

[farfromrefug]

@bnoordhuis I tried without the firewall and it does the same.
But actually trying with python is a good idea. Will try that

And sorry didn't know about the help repo.
Thanks