Strange connection problem with Iphone

[koraybilgi]

Hi @Goddchen,

I'm having a strange problem. I am trying to connect to a VNC server on my local network. When I run the flutter code in the Simulator application, I can connect without any problems. But when I run the code on a physical iPhone, the Progress Indicator does not disappear, the remote window does not shown, and it does not print any error logs.

As far as I understand from the VNC server logs, the code run on the Iphone terminates the connection with the vnc server after establishing. But as I mentioned before, there are no logs on the flutter side explains why.

My environment info and logs are below.
Thanks in advance for your help.

Server:
OS: Ubuntu 22.04
VNC server: x11vnc 0.9.13 lastmod: 2011-08-10
RFB Version: 3.8

Iphone:
Model: Iphone 12
IOS: 16.6

Simulator:
Model: Iphone 14
IOS: 16.6

Simulator's Debug Console Output:

Launching lib/main.dart on iPhone 14 in debug mode...
main.dart:1
Xcode build done.                                           17.6s
Connecting to VM Service at ws://127.0.0.1:62816/flcn_VlyMIg=/ws
flutter: INFO RemoteFrameBufferClient: < RemoteFrameBufferProtocolVersionHandshakeMessage(version: RemoteFrameBufferProtocolVersion.v3_8())
flutter: INFO RemoteFrameBufferClient: > RemoteFrameBufferProtocolVersionHandshakeMessage(version: RemoteFrameBufferProtocolVersion.v3_8())
flutter: INFO RemoteFrameBufferClient: < numberOfSecurityTypes=1
flutter: INFO RemoteFrameBufferClient: < RemoteFrameBufferSecurityHandshakeMessage(securityTypes: (RemoteFrameBufferSecurityType.none()))
flutter: INFO RemoteFrameBufferClient: > RemoteFrameBufferSecurityType.none()
flutter: INFO RemoteFrameBufferClient: < RemoteFrameBufferSecurityResultHandshakeMessage(success: true)
flutter: INFO RemoteFrameBufferClient: > RemoteFrameBufferClientInitMessage(sharedFlag: true)
flutter: INFO RemoteFrameBufferClient: < RemoteFrameBufferServerInitMessage(frameBufferHeightInPixels: 1755, frameBufferWidthInPixels: 900, name: 5823dba790e9:44, serverPixelFormat: RemoteFrameBufferPixelFormat(bitsPerPixel: 32, depth: 24, bigEndian: false, trueColor: true, redMax: 255, greenMax: 255, blueMax: 255, redShift: 16, greenShift: 8, blueShift: 0))
flutter: INFO RemoteFrameBufferClient: > RemoteFrameBufferSetPixelFormatMessage(pixelFormat: RemoteFrameBufferPixelFormat(bitsPerPixel: 32, depth: 24, bigEndian: false, trueColor: true, redMax: 255, greenMax: 255, blueMax: 255, redShift: 16, greenShift: 8, blueShift: 0))
flutter: INFO RemoteFrameBufferClient: > RemoteFrameBufferSetEncodingsMessage(encodingTypes: [RemoteFrameBufferEncodingType.copyRect(), RemoteFrameBufferEncodingType.raw()])
flutter: INFO RemoteFrameBufferClient: > RemoteFrameBufferFrameBufferUpdateRequestMessage(height: 1755, incremental: true, width: 900, x: 0, y: 0)
flutter: INFO RemoteFrameBufferClient: < messageType: 0
flutter: FINE RemoteFrameBufferClient: < 1 rectangles
flutter: FINE RemoteFrameBufferClient: < RemoteFrameBufferFrameBufferUpdateMessageRectangleHeader(encodingType: RemoteFrameBufferEncodingType.raw(), height: 1755, width: 900, x: 0, y: 0)
flutter: INFO RemoteFrameBufferClient: < update rectangles: {RemoteFrameBufferEncodingType.raw(): 1}
flutter: INFO RemoteFrameBufferClient: > RemoteFrameBufferFrameBufferUpdateRequestMessage(height: 1755, incremental: true, width: 900, x: 0, y: 0)

Iphone's Debug Console Output:

Launching lib/main.dart on Koray’s iPhone in debug mode...
main.dart:1
Automatically signing iOS for device deployment using specified development team in Xcode project: XXX
Xcode build done.                                           13.5s
Connecting to VM Service at ws://127.0.0.1:61431/-8aUd-ArsWM=/ws
Successfully load keyboard extensions
flutter: INFO RemoteFrameBufferClient: < RemoteFrameBufferProtocolVersionHandshakeMessage(version: RemoteFrameBufferProtocolVersion.v3_8())
flutter: INFO RemoteFrameBufferClient: > RemoteFrameBufferProtocolVersionHandshakeMessage(version: RemoteFrameBufferProtocolVersion.v3_8())
flutter: INFO RemoteFrameBufferClient: < numberOfSecurityTypes=1
flutter: INFO RemoteFrameBufferClient: < RemoteFrameBufferSecurityHandshakeMessage(securityTypes: (RemoteFrameBufferSecurityType.none()))
flutter: INFO RemoteFrameBufferClient: > RemoteFrameBufferSecurityType.none()
flutter: INFO RemoteFrameBufferClient: < RemoteFrameBufferSecurityResultHandshakeMessage(success: true)
flutter: INFO RemoteFrameBufferClient: > RemoteFrameBufferClientInitMessage(sharedFlag: true)
flutter: INFO RemoteFrameBufferClient: < RemoteFrameBufferServerInitMessage(frameBufferHeightInPixels: 1755, frameBufferWidthInPixels: 900, name: 2717f4d03671:44, serverPixelFormat: RemoteFrameBufferPixelFormat(bitsPerPixel: 32, depth: 24, bigEndian: false, trueColor: true, redMax: 255, greenMax: 255, blueMax: 255, redShift: 16, greenShift: 8, blueShift: 0))
flutter: INFO RemoteFrameBufferClient: > RemoteFrameBufferSetPixelFormatMessage(pixelFormat: RemoteFrameBufferPixelFormat(bitsPerPixel: 32, depth: 24, bigEndian: false, trueColor: true, redMax: 255, greenMax: 255, blueMax: 255, redShift: 16, greenShift: 8, blueShift: 0))
flutter: INFO RemoteFrameBufferClient: > RemoteFrameBufferSetEncodingsMessage(encodingTypes: [RemoteFrameBufferEncodingType.copyRect(), RemoteFrameBufferEncodingType.raw()])
flutter: INFO RemoteFrameBufferClient: > RemoteFrameBufferFrameBufferUpdateRequestMessage(height: 1755, incremental: true, width: 900, x: 0, y: 0)
flutter: INFO RemoteFrameBufferClient: < messageType: 0
flutter: FINE RemoteFrameBufferClient: < 1 rectangles
flutter: FINE RemoteFrameBufferClient: < RemoteFrameBufferFrameBufferUpdateMessageRectangleHeader(encodingType: RemoteFrameBufferEncodingType.raw(), height: 1755, width: 900, x: 0, y: 0)

VNC Server Log Diff (Left: Simulator, Right: Iphone)
Both logs are until closing the app. Iphone prints Client 172.17.0.1 gone immediately after connecting.

[recepkoseoglu]

+1

[Goddchen]

Thanks for reporting this. Unfortunately I don't have a physical iPhone at hand right now 🫤 Do you have the possibility to run the code and set a breakpoint for uncaught exceptions to see if something slips the error handling?