diff --git a/eng/Versions.props b/eng/Versions.props
index e86eb1601c..aa382cd021 100644
--- a/eng/Versions.props
+++ b/eng/Versions.props
@@ -221,7 +221,7 @@
     <CastleCorePackageVersion>4.2.1</CastleCorePackageVersion>
     <FSharpCorePackageVersion>4.2.1</FSharpCorePackageVersion>
     <GoogleProtobufPackageVersion>3.8.0</GoogleProtobufPackageVersion>
-    <GrpcAspNetCorePackageVersion>0.1.22-pre2</GrpcAspNetCorePackageVersion>
+    <GrpcAspNetCorePackageVersion>0.1.22-pre3</GrpcAspNetCorePackageVersion>
     <IdentityServer4AspNetIdentityPackageVersion>3.0.0-preview3.4</IdentityServer4AspNetIdentityPackageVersion>
     <IdentityServer4EntityFrameworkPackageVersion>3.0.0-preview3.4</IdentityServer4EntityFrameworkPackageVersion>
     <IdentityServer4PackageVersion>3.0.0-preview3.4</IdentityServer4PackageVersion>
diff --git a/src/ProjectTemplates/Web.ProjectTemplates/content/GrpcService-CSharp/Program.cs b/src/ProjectTemplates/Web.ProjectTemplates/content/GrpcService-CSharp/Program.cs
index 94905231a0..d1f9df7226 100644
--- a/src/ProjectTemplates/Web.ProjectTemplates/content/GrpcService-CSharp/Program.cs
+++ b/src/ProjectTemplates/Web.ProjectTemplates/content/GrpcService-CSharp/Program.cs
@@ -15,6 +15,8 @@ namespace GrpcService_CSharp
             CreateHostBuilder(args).Build().Run();
         }
 
+        // Additional configuration is required to successfully run gRPC on macOS.
+        // For instructions on how to configure Kestrel and gRPC clients on macOS, visit https://go.microsoft.com/fwlink/?linkid=2099682
         public static IHostBuilder CreateHostBuilder(string[] args) =>
             Host.CreateDefaultBuilder(args)
                 .ConfigureWebHostDefaults(webBuilder =>
diff --git a/src/ProjectTemplates/Web.Spa.ProjectTemplates/content/Angular-CSharp/.template.config/template.json b/src/ProjectTemplates/Web.Spa.ProjectTemplates/content/Angular-CSharp/.template.config/template.json
index 93dd531436..f919655bd8 100644
--- a/src/ProjectTemplates/Web.Spa.ProjectTemplates/content/Angular-CSharp/.template.config/template.json
+++ b/src/ProjectTemplates/Web.Spa.ProjectTemplates/content/Angular-CSharp/.template.config/template.json
@@ -6,6 +6,7 @@
     "SPA"
   ],
   "groupIdentity": "Microsoft.DotNet.Web.Spa.ProjectTemplates.Angular",
+  "precedence": "5000",
   "identity": "Microsoft.DotNet.Web.Spa.ProjectTemplates.Angular.CSharp.3.0",
   "name": "ASP.NET Core with Angular",
   "preferNameDirectory": true,
diff --git a/src/ProjectTemplates/Web.Spa.ProjectTemplates/content/React-CSharp/.template.config/template.json b/src/ProjectTemplates/Web.Spa.ProjectTemplates/content/React-CSharp/.template.config/template.json
index 7eff01916f..3c4b69d0b9 100644
--- a/src/ProjectTemplates/Web.Spa.ProjectTemplates/content/React-CSharp/.template.config/template.json
+++ b/src/ProjectTemplates/Web.Spa.ProjectTemplates/content/React-CSharp/.template.config/template.json
@@ -6,6 +6,7 @@
     "SPA"
   ],
   "groupIdentity": "Microsoft.DotNet.Web.Spa.ProjectTemplates.React",
+  "precedence": "5000",
   "identity": "Microsoft.DotNet.Web.Spa.ProjectTemplates.React.CSharp.3.0",
   "name": "ASP.NET Core with React.js",
   "preferNameDirectory": true,
@@ -189,7 +190,6 @@
       "binding": "HostIdentifier"
     }
   },
-
   "tags": {
     "language": "C#",
     "type": "project"
diff --git a/src/ProjectTemplates/Web.Spa.ProjectTemplates/content/ReactRedux-CSharp/.template.config/template.json b/src/ProjectTemplates/Web.Spa.ProjectTemplates/content/ReactRedux-CSharp/.template.config/template.json
index 660c888df4..264061a004 100644
--- a/src/ProjectTemplates/Web.Spa.ProjectTemplates/content/ReactRedux-CSharp/.template.config/template.json
+++ b/src/ProjectTemplates/Web.Spa.ProjectTemplates/content/ReactRedux-CSharp/.template.config/template.json
@@ -6,6 +6,7 @@
     "SPA"
   ],
   "groupIdentity": "Microsoft.DotNet.Web.Spa.ProjectTemplates.ReactRedux",
+  "precedence": "5000",
   "identity": "Microsoft.DotNet.Web.Spa.ProjectTemplates.ReactRedux.CSharp.3.0",
   "name": "ASP.NET Core with React.js and Redux",
   "preferNameDirectory": true,
diff --git a/src/SignalR/server/Core/ref/Microsoft.AspNetCore.SignalR.Core.netcoreapp3.0.cs b/src/SignalR/server/Core/ref/Microsoft.AspNetCore.SignalR.Core.netcoreapp3.0.cs
index 6e2f3f1f71..5309dae32c 100644
--- a/src/SignalR/server/Core/ref/Microsoft.AspNetCore.SignalR.Core.netcoreapp3.0.cs
+++ b/src/SignalR/server/Core/ref/Microsoft.AspNetCore.SignalR.Core.netcoreapp3.0.cs
@@ -144,6 +144,7 @@ namespace Microsoft.AspNetCore.SignalR
         public HubConnectionContextOptions() { }
         public System.TimeSpan ClientTimeoutInterval { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
         public System.TimeSpan KeepAliveInterval { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
+        public long? MaximumReceiveMessageSize { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
         public int StreamBufferCapacity { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
     }
     public partial class HubConnectionHandler<THub> : Microsoft.AspNetCore.Connections.ConnectionHandler where THub : Microsoft.AspNetCore.SignalR.Hub
diff --git a/src/SignalR/server/Core/src/HubConnectionContext.cs b/src/SignalR/server/Core/src/HubConnectionContext.cs
index ba3a8a0201..cfc0137b36 100644
--- a/src/SignalR/server/Core/src/HubConnectionContext.cs
+++ b/src/SignalR/server/Core/src/HubConnectionContext.cs
@@ -43,6 +43,7 @@ namespace Microsoft.AspNetCore.SignalR
         private bool _clientTimeoutActive;
         private bool _connectionAborted;
         private int _streamBufferCapacity;
+        private long? _maxMessageSize;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="HubConnectionContext"/> class.
@@ -55,6 +56,7 @@ namespace Microsoft.AspNetCore.SignalR
             _keepAliveInterval = contextOptions.KeepAliveInterval.Ticks;
             _clientTimeoutInterval = contextOptions.ClientTimeoutInterval.Ticks;
             _streamBufferCapacity = contextOptions.StreamBufferCapacity;
+            _maxMessageSize = contextOptions.MaximumReceiveMessageSize;
 
             _connectionContext = connectionContext;
             _logger = loggerFactory.CreateLogger<HubConnectionContext>();
@@ -406,10 +408,20 @@ namespace Microsoft.AspNetCore.SignalR
 
                             if (!buffer.IsEmpty)
                             {
-                                if (HandshakeProtocol.TryParseRequestMessage(ref buffer, out var handshakeRequestMessage))
+                                var segment = buffer;
+                                var overLength = false;
+
+                                if (_maxMessageSize != null && buffer.Length > _maxMessageSize.Value)
+                                {
+                                    // We give the parser a sliding window of the default message size
+                                    segment = segment.Slice(segment.Start, _maxMessageSize.Value);
+                                    overLength = true;
+                                }
+
+                                if (HandshakeProtocol.TryParseRequestMessage(ref segment, out var handshakeRequestMessage))
                                 {
                                     // We parsed the handshake
-                                    consumed = buffer.Start;
+                                    consumed = segment.Start;
                                     examined = consumed;
 
                                     Protocol = protocolResolver.GetProtocol(handshakeRequestMessage.Protocol, supportedProtocols);
@@ -461,6 +473,12 @@ namespace Microsoft.AspNetCore.SignalR
                                     await WriteHandshakeResponseAsync(HandshakeResponseMessage.Empty);
                                     return true;
                                 }
+                                else if (overLength)
+                                {
+                                    Log.HandshakeSizeLimitExceeded(_logger, _maxMessageSize.Value);
+                                    await WriteHandshakeResponseAsync(new HandshakeResponseMessage("Handshake was canceled."));
+                                    return false;
+                                }
                             }
 
                             if (result.IsCompleted)
@@ -619,6 +637,9 @@ namespace Microsoft.AspNetCore.SignalR
             private static readonly Action<ILogger, int, Exception> _clientTimeout =
                 LoggerMessage.Define<int>(LogLevel.Debug, new EventId(9, "ClientTimeout"), "Client timeout ({ClientTimeout}ms) elapsed without receiving a message from the client. Closing connection.");
 
+            private static readonly Action<ILogger, long, Exception> _handshakeSizeLimitExceeded =
+                LoggerMessage.Define<long>(LogLevel.Debug, new EventId(10, "HandshakeSizeLimitExceeded"), "The maximum message size of {MaxMessageSize}B was exceeded while parsing the Handshake. The message size can be configured in AddHubOptions.");
+
             public static void HandshakeComplete(ILogger logger, string hubProtocol)
             {
                 _handshakeComplete(logger, hubProtocol, null);
@@ -663,6 +684,11 @@ namespace Microsoft.AspNetCore.SignalR
             {
                 _clientTimeout(logger, (int)timeout.TotalMilliseconds, null);
             }
+
+            public static void HandshakeSizeLimitExceeded(ILogger logger, long maxMessageSize)
+            {
+                _handshakeSizeLimitExceeded(logger, maxMessageSize, null);
+            }
         }
     }
 }
diff --git a/src/SignalR/server/Core/src/HubConnectionContextOptions.cs b/src/SignalR/server/Core/src/HubConnectionContextOptions.cs
index a38096cbef..c95c58afe6 100644
--- a/src/SignalR/server/Core/src/HubConnectionContextOptions.cs
+++ b/src/SignalR/server/Core/src/HubConnectionContextOptions.cs
@@ -24,5 +24,10 @@ namespace Microsoft.AspNetCore.SignalR
         /// Gets or sets the max buffer size for client upload streams.
         /// </summary>
         public int StreamBufferCapacity { get; set; }
+
+        /// <summary>
+        /// Gets or sets the maximum message size the client can send.
+        /// </summary>
+        public long? MaximumReceiveMessageSize { get; set; }
     }
 }
diff --git a/src/SignalR/server/Core/src/HubConnectionHandler.cs b/src/SignalR/server/Core/src/HubConnectionHandler.cs
index de6a3dd3c0..270eb44c0c 100644
--- a/src/SignalR/server/Core/src/HubConnectionHandler.cs
+++ b/src/SignalR/server/Core/src/HubConnectionHandler.cs
@@ -89,6 +89,7 @@ namespace Microsoft.AspNetCore.SignalR
                 KeepAliveInterval = _hubOptions.KeepAliveInterval ?? _globalHubOptions.KeepAliveInterval ?? HubOptionsSetup.DefaultKeepAliveInterval,
                 ClientTimeoutInterval = _hubOptions.ClientTimeoutInterval ?? _globalHubOptions.ClientTimeoutInterval ?? HubOptionsSetup.DefaultClientTimeoutInterval,
                 StreamBufferCapacity = _hubOptions.StreamBufferCapacity ?? _globalHubOptions.StreamBufferCapacity ?? HubOptionsSetup.DefaultStreamBufferCapacity,
+                MaximumReceiveMessageSize = _maximumMessageSize,
             };
 
             Log.ConnectedStarting(_logger);
diff --git a/src/SignalR/server/SignalR/test/HubConnectionHandlerTests.cs b/src/SignalR/server/SignalR/test/HubConnectionHandlerTests.cs
index d4188e3918..f2eb574c9d 100644
--- a/src/SignalR/server/SignalR/test/HubConnectionHandlerTests.cs
+++ b/src/SignalR/server/SignalR/test/HubConnectionHandlerTests.cs
@@ -292,6 +292,40 @@ namespace Microsoft.AspNetCore.SignalR.Tests
             }
         }
 
+        [Fact]
+        public async Task ConnectionClosedWhenHandshakeLargerThanMaxMessageSize()
+        {
+            using (StartVerifiableLog())
+            {
+                var connectionHandler = HubConnectionHandlerTestUtils.GetHubConnectionHandler(typeof(HubT), loggerFactory: LoggerFactory,
+                    builder =>
+                    {
+                        builder.AddSignalR(o =>
+                        {
+                            o.MaximumReceiveMessageSize = 1;
+                        });
+                    });
+
+                using (var client = new TestClient())
+                {
+                    client.SupportedFormats = TransferFormat.Text;
+
+                    var connectionHandlerTask = await client.ConnectAsync(connectionHandler,
+                                                            sendHandshakeRequestMessage: true,
+                                                            expectedHandshakeResponseMessage: false);
+
+                    var message = await client.ReadAsync(isHandshake: true).OrTimeout();
+
+                    Assert.Equal("Handshake was canceled.", ((HandshakeResponseMessage)message).Error);
+
+                    // Connection closes
+                    await connectionHandlerTask.OrTimeout();
+
+                    client.Dispose();
+                }
+            }
+        }
+
         [Fact]
         public async Task SendingHandshakeRequestInChunksWorks()
         {