ALVR connection refused os error 111 on UDP on Oculus Quest 2

[skabrits]

Description

When trying to connect to Oculus Quest 2 directly (by IP) with UDP protocol connection fails with message "Client disconnected. Cause: Connection refused (os error 111)". netstat shows that in the beginning ALVR establishes TCP connection to port 9944 of Oculus Quest, which then dies.

Meanwhile when using TCP protocol app works correctly, connection is being established and stream starts. This issue might be connected to ALVR Handshake Error #1727, as that seems to have similar workaround.

General Troubleshooting

• I carefully followed the instructions in the README and successfully completed the setup wizard
• I read the ALVR GitHub Wiki

Environment

Hardware

Note: for Linux, an upload to the hw-probe database is preferred: hw-probe -all -upload

CPU: 16 × Intel® Core™ i9-9980HK CPU @ 2.40GHz

GPU: NVIDIA GeForce RTX 4070

GPU Driver Version: 560.35.03

Audio: PulseAudio

Installation

ALVR Version: 20.11.1

ALVR Settings File: session.json

SteamVR Version: 2.8.8

SteamVR launched with options: QT_QPA_PLATFORM=xcb WAYLAND_DISPLAY='' /home/ubuntu/.steam/steam/steamapps/common/SteamVR/bin/vrmonitor.sh %command%

Install Type:

• Packaged (exe, deb, rpm, etc)
• Portable (zip)
• Source

OS Name and Version (winver on Windows or grep PRETTY_NAME /etc/os-release on most Linux distributions): Ubuntu 24.04.01 LTS

Logs

01:05:14.588 [WARNING] XRandR reported that the display's 0mm in size, which is certifiably insane
01:05:14.671 [INFO] Guessed window scale factor: 1
[SESSION] Updated
01:06:24.747 [INFO] Server connected
01:08:59.587 [INFO] Initial socket buffer size: send: 87040B, recv: 131072B
01:08:59.624 [INFO] Initial socket buffer size: send: 212992B, recv: 212992B
01:08:59.624 [INFO] Set socket send buffer succeeded: 425984
01:08:59.624 [INFO] Set socket recv buffer succeeded: 425984
01:08:59.628 [INFO] Render Target: 3072 1664
01:08:59.629 [INFO] Refresh Rate: 60
01:08:59.629 [INFO] CEncoder::Run
01:08:59.629 [INFO] CEncoder Listening
01:08:59.671 [INFO] Client disconnected. Cause: Connection refused (os error 111)
01:08:59.727 [INFO] CEncoder client connected, pid 5564, cmdline /home/ubuntu/.steam/debian-installation/steamapps/common/SteamVR/bin/linux64/vrcompositor
01:08:59.788 [INFO] Using Vulkan device NVIDIA GeForce RTX 4070
01:08:59.971 [INFO] Using device path /dev/dri/renderD129
01:08:59.977 [INFO] FrameRender: Input size 3072x1664
01:08:59.978 [INFO] FrameRender: Output size 1856x864
01:09:00.112 [INFO] Using NvEnc encoder
01:09:04.607 [INFO] Initial socket buffer size: send: 87040B, recv: 131072B
01:09:04.635 [INFO] Initial socket buffer size: send: 212992B, recv: 212992B
01:09:04.635 [INFO] Set socket send buffer succeeded: 425984
01:09:04.635 [INFO] Set socket recv buffer succeeded: 425984
01:09:04.638 [INFO] Render Target: 3072 1664
01:09:04.638 [INFO] Refresh Rate: 60
01:09:04.657 [INFO] Received new playspace with size: [3.4070659, 1.6286782]
01:09:04.675 [INFO] Client disconnected. Cause: Connection refused (os error 111)
01:09:06.613 [INFO] Initial socket buffer size: send: 87040B, recv: 131072B
01:09:06.639 [INFO] Initial socket buffer size: send: 212992B, recv: 212992B
01:09:06.639 [INFO] Set socket send buffer succeeded: 425984
01:09:06.639 [INFO] Set socket recv buffer succeeded: 425984
01:09:06.641 [INFO] Render Target: 3072 1664
01:09:06.641 [INFO] Refresh Rate: 60
01:09:06.660 [INFO] Received new playspace with size: [3.4070659, 1.6286782]
01:09:06.666 [INFO] Client disconnected. Cause: Connection refused (os error 111)
01:09:10.636 [INFO] Initial socket buffer size: send: 87040B, recv: 131072B
01:09:10.663 [INFO] Initial socket buffer size: send: 212992B, recv: 212992B
01:09:10.663 [INFO] Set socket send buffer succeeded: 425984
01:09:10.663 [INFO] Set socket recv buffer succeeded: 425984
01:09:10.665 [INFO] Render Target: 3072 1664
01:09:10.665 [INFO] Refresh Rate: 60
01:09:10.689 [INFO] Received new playspace with size: [3.4070659, 1.6286782]
01:09:10.692 [INFO] Client disconnected. Cause: Connection refused (os error 111)

[skabrits]

Indeed, ALVR 20.0.0 client allows connecting via UDP as mentioned in ALVR Handshake Error