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SocketException: Permission denied on Ubuntu 18.04 with default ports

See original GitHub issue

Describe the bug

When starting .Net Core 2.2 application On freshly installed and patched Ubuntu 18.04 Linux As an unprivileged linux user With both TCP and TLS default ports configured Application crashes with:

Unhandled Exception: System.Net.Sockets.SocketException: Permission denied

Which project is your bug related to?

MQTTnet.Server standalone

To Reproduce

Steps to reproduce the behavior:

Using this version of MQTTnet ‘3.0.5’.
Run this code ‘See code below’.
With these arguments ‘dotnet run’.
See error.

Expected behavior

Application starts up correctly.

Screenshots

Not applicable.

Additional context / logging

mqtt@Ubuntu18.04:~/mqtt_server$ dotnet run
Environment: Development

Unhandled Exception: System.Net.Sockets.SocketException: Permission denied
at System.Net.Sockets.Socket.UpdateStatusAfterSocketErrorAndThrowException(SocketError error, String callerName)
at System.Net.Sockets.Socket.SetSocketOption(SocketOptionLevel optionLevel, SocketOptionName optionName, Int32 optionValue, Boolean silent)
at System.Net.Sockets.Socket.SetSocketOption(SocketOptionLevel optionLevel, SocketOptionName optionName, Int32 optionValue)
at MQTTnet.Implementations.MqttTcpServerListener.Start(Boolean treatErrorsAsWarning, CancellationToken cancellationToken)
at MQTTnet.Implementations.MqttTcpServerAdapter.RegisterListeners(MqttServerTcpEndpointBaseOptions options, X509Certificate2 tlsCertificate, CancellationToken cancellationToken)
at MQTTnet.Implementations.MqttTcpServerAdapter.StartAsync(IMqttServerOptions options)
at MQTTnet.Server.MqttServer.StartAsync(IMqttServerOptions options)
at mqtt_server.Program.Main() in /home/mqtt/iot/mqtt_server/Program.cs:line 58
at mqtt_server.Program.<Main>()

mqtt@Ubuntu18.04:~/mqtt_server$ strace -f -s 20 -e trace=%network dotnet run -c Debug
strace: Process 2451 attached
strace: Process 2452 attached

...

Environment: Development
strace: Process 2514 attached
strace: Process 2515 attached
strace: Process 2516 attached
strace: Process 2517 attached
strace: Process 2518 attached
strace: Process 2519 attached
[pid  2503] socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC, IPPROTO_TCP) = 100
[pid  2503] setsockopt(100, SOL_SOCKET, SO_DEBUG, [1], 4) = -1 EACCES (Permission denied)

Unhandled Exception: System.Net.Sockets.SocketException: Permission denied
...

Code example

var certificate = new X509Certificate2(@"certificate.pfx", "[REDACTED]", X509KeyStorageFlags.Exportable);

var optionsBuilder = new MqttServerOptionsBuilder()
		  .WithDefaultEndpointPort(1883)
		  .WithEncryptedEndpoint()
		  .WithEncryptedEndpointPort(1884)
		  .WithEncryptionCertificate(certificate.Export(X509ContentType.Pfx))
		  .WithEncryptionSslProtocol(SslProtocols.Tls12)
		  .WithPersistentSessions()
		  .WithConnectionBacklog(100)
		  .WithApplicationMessageInterceptor(async context => {
			  // handler code
			  }
		  })
		  .WithMaxPendingMessagesPerClient(3)
		  .WithConnectionBacklog(100)
		  .WithStorage(new RetainedMessageHandler())
		  .WithDefaultCommunicationTimeout(TimeSpan.FromMinutes(5))
	 ;

var mqttServer = new MqttFactory().CreateMqttServer();
await mqttServer.StartAsync(optionsBuilder.Build());
...