I have a (Spring Boot) server, and a client trying to establish a Websockets connection to the server.
I've run and tested the server on a Linux machine (Ubuntu 20.04), it works fine. It also ran fine on my Windows (Windows 10 Home) machine up until a few days ago. Now it is acting strange.
I checked the network traffic between client and server in wireshark, both in Linux and Windows.
Here is the linux capture:
And this is the windows capture:
The blacked out IPs are the client's. Both the linux and windows servers are running in the same network, so the problem would not be in a router configuration.
In both cases, the client makes the same request to /location/websocket, but in Linux the server responds successfully in less than 1 second, while in Windows it responds about 13 seconds later, and immediately follows the response by closing the websocket connection.
What looks strange to me are the NBSTAT name queries. I tried several times and there are always three queries between the arrival of the client request, and the closing of the websocket connection.
So maybe the windows machine needs to do a name query to respond successfully? Is this normal? What does the <00>...<00> string in the name query mean? I checked the network traffic while keeping the server up but not connecting to the client, and I didn't see any activity on port 137, so it definitely only happens when the client tries to contact the windows machine. What can I do about this? How can I get the server responding to websocket connections again?
