Added the bound IP address to the server options.

Frameworks/MQTTnet.NetStandard/Implementations/MqttServerAdapter.cs

@@ -39,7 +39,7 @@ namespace MQTTnet.Implementations
             if (options.DefaultEndpointOptions.IsEnabled)
             {
                 _defaultEndpointSocket = new Socket(SocketType.Stream, ProtocolType.Tcp);
-                _defaultEndpointSocket.Bind(new IPEndPoint(IPAddress.Any, options.GetDefaultEndpointPort()));
+                _defaultEndpointSocket.Bind(new IPEndPoint(options.DefaultEndpointOptions.BoundIPAddress, options.GetDefaultEndpointPort()));
                 _defaultEndpointSocket.Listen(options.ConnectionBacklog);
 
                 Task.Run(async () => await AcceptDefaultEndpointConnectionsAsync(_cancellationTokenSource.Token).ConfigureAwait(false), _cancellationTokenSource.Token).ConfigureAwait(false);
@@ -59,7 +59,7 @@ namespace MQTTnet.Implementations
                 }
 
                 _tlsEndpointSocket = new Socket(SocketType.Stream, ProtocolType.Tcp);
-                _tlsEndpointSocket.Bind(new IPEndPoint(IPAddress.Any, options.GetTlsEndpointPort()));
+                _tlsEndpointSocket.Bind(new IPEndPoint(options.TlsEndpointOptions.BoundIPAddress, options.GetTlsEndpointPort()));
                 _tlsEndpointSocket.Listen(options.ConnectionBacklog);
 
                 Task.Run(async () => await AcceptTlsEndpointConnectionsAsync(_cancellationTokenSource.Token).ConfigureAwait(false), _cancellationTokenSource.Token).ConfigureAwait(false);

Frameworks/MQTTnet.NetStandard/Server/IMqttServerOptions.cs

@@ -1,16 +1,20 @@
 using System;
+using System.Net;
 
 namespace MQTTnet.Server
 {
     public interface IMqttServerOptions
     {
-        Action<MqttApplicationMessageInterceptorContext> ApplicationMessageInterceptor { get; }
         int ConnectionBacklog { get; }
-        Action<MqttConnectionValidatorContext> ConnectionValidator { get; }
         TimeSpan DefaultCommunicationTimeout { get; }
-        MqttServerDefaultEndpointOptions DefaultEndpointOptions { get; }
-        IMqttServerStorage Storage { get; }
+
+        Action<MqttConnectionValidatorContext> ConnectionValidator { get; }
         Action<MqttSubscriptionInterceptorContext> SubscriptionInterceptor { get; }
+        Action<MqttApplicationMessageInterceptorContext> ApplicationMessageInterceptor { get; }
+
+        MqttServerDefaultEndpointOptions DefaultEndpointOptions { get; }
         MqttServerTlsEndpointOptions TlsEndpointOptions { get; }
+
+        IMqttServerStorage Storage { get; }
     }
 }

Frameworks/MQTTnet.NetStandard/Server/MqttServerDefaultEndpointOptions.cs

@@ -1,9 +1,13 @@
-namespace MQTTnet.Server
+using System.Net;
+
+namespace MQTTnet.Server
 {
     public sealed class MqttServerDefaultEndpointOptions
     {
         public bool IsEnabled { get; set; } = true;
 
         public int? Port { get; set; }
+
+        public IPAddress BoundIPAddress { get; set; } = IPAddress.Any;
     }
 }

Frameworks/MQTTnet.NetStandard/Server/MqttServerOptionsBuilder.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Net;
 
 namespace MQTTnet.Server
 {
@@ -18,33 +19,45 @@ namespace MQTTnet.Server
             return this;
         }
 
-        public MqttServerOptionsBuilder WithDefaultEndpointPort(int value)
+        public MqttServerOptionsBuilder WithDefaultEndpoint()
         {
-            _options.DefaultEndpointOptions.Port = value;
+            _options.DefaultEndpointOptions.IsEnabled = true;
             return this;
         }
 
-        public MqttServerOptionsBuilder WithDefaultEndpoint()
+        public MqttServerOptionsBuilder WithDefaultEndpointPort(int? value)
         {
-            _options.DefaultEndpointOptions.IsEnabled = true;
+            _options.DefaultEndpointOptions.Port = value;
             return this;
         }
 
+        public MqttServerOptionsBuilder WithDefaultEndpointBoundIPAddress(IPAddress value)
+        {
+            _options.DefaultEndpointOptions.BoundIPAddress = value ?? IPAddress.Any;
+            return this;
+        }
+        
         public MqttServerOptionsBuilder WithoutDefaultEndpoint()
         {
             _options.DefaultEndpointOptions.IsEnabled = false;
             return this;
         }
-
+        
         public MqttServerOptionsBuilder WithEncryptedEndpoint()
         {
             _options.TlsEndpointOptions.IsEnabled = true;
             return this;
         }
 
-        public MqttServerOptionsBuilder WithoutEncryptedEndpoint()
+        public MqttServerOptionsBuilder WithEncryptedEndpointPort(int? value)
         {
-            _options.TlsEndpointOptions.IsEnabled = false;
+            _options.TlsEndpointOptions.Port = value;
+            return this;
+        }
+
+        public MqttServerOptionsBuilder WithEncryptedEndpointBoundIPAddress(IPAddress value)
+        {
+            _options.TlsEndpointOptions.BoundIPAddress = value;
             return this;
         }
 
@@ -54,6 +67,12 @@ namespace MQTTnet.Server
             return this;
         }
 
+        public MqttServerOptionsBuilder WithoutEncryptedEndpoint()
+        {
+            _options.TlsEndpointOptions.IsEnabled = false;
+            return this;
+        }
+        
         public MqttServerOptionsBuilder WithStorage(IMqttServerStorage value)
         {
             _options.Storage = value;

Frameworks/MQTTnet.NetStandard/Server/MqttServerTlsEndpointOptions.cs

@@ -1,4 +1,6 @@
-namespace MQTTnet.Server
+using System.Net;
+
+namespace MQTTnet.Server
 {
     public sealed class MqttServerTlsEndpointOptions
     {
@@ -7,5 +9,7 @@
         public int? Port { get; set; }
 
         public byte[] Certificate { get; set; }
+
+        public IPAddress BoundIPAddress { get; set; } = IPAddress.Any;
     }
 }