diff --git a/.vscode/launch.json b/.vscode/launch.json
index e91f61ede0..f97435a509 100644
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -12,8 +12,7 @@
       "type": "coreclr",
       "request": "launch",
       "preLaunchTask": "Compile: solution",
-      "program": "${workspaceRoot}/samples/SampleApp/bin/Debug/netcoreapp1.1/SampleApp.dll",
-      "args": [],
+      "program": "${workspaceRoot}/samples/SampleApp/bin/Debug/netcoreapp2.0/SampleApp.dll",
       "cwd": "${workspaceRoot}/samples/SampleApp",
       "console": "internalConsole",
       "stopAtEntry": false,
@@ -38,8 +37,7 @@
       "type": "coreclr",
       "request": "launch",
       "preLaunchTask": "Compile: solution",
-      "program": "${workspaceRoot}/samples/LargeResponseApp/bin/Debug/netcoreapp1.1/LargeResponseApp.dll",
-      "args": [],
+      "program": "${workspaceRoot}/samples/LargeResponseApp/bin/Debug/netcoreapp2.0/LargeResponseApp.dll",
       "cwd": "${workspaceRoot}/samples/LargeResponseApp",
       "console": "internalConsole",
       "stopAtEntry": false,
diff --git a/.vscode/tasks.json b/.vscode/tasks.json
index b5ff23e775..db382e6056 100644
--- a/.vscode/tasks.json
+++ b/.vscode/tasks.json
@@ -5,10 +5,20 @@
       "DOTNET_SKIP_FIRST_TIME_EXPERIENCE": "true"
     }
   },
+  // requires that you first run build.cmd or build.sh to install local builds of dotnet
+  "windows": {
+    "command": "${env.LOCALAPPDATA}/Microsoft/dotnet/dotnet.exe"
+  },
+  "osx": {
+    "command": "${env.HOME}/.dotnet/dotnet"
+  },
+  "linux": {
+    "command": "${env.HOME}/.dotnet/dotnet"
+  },
+  "suppressTaskName": true,
   "tasks": [
     {
       "taskName": "Restore: solution",
-      "command": "dotnet",
       "args": [
         "restore"
       ]
@@ -16,7 +26,6 @@
     {
       "taskName": "Compile: solution",
       "isBuildCommand": true,
-      "command": "dotnet",
       "args": [
         "build",
         "${workspaceRoot}/KestrelHttpServer.sln"
@@ -40,9 +49,16 @@
         }
       }
     },
+    {
+      "taskName": "Test",
+      "args": [
+        "test"
+      ],
+      "problemMatcher": "$msCompile",
+      "isTestCommand": true
+    },
     {
       "taskName": "Compile: CodeGenerator",
-      "command": "dotnet",
       "args": [
         "build"
       ],
@@ -53,7 +69,6 @@
     },
     {
       "taskName": "Run: CodeGenerator",
-      "command": "dotnet",
       "args": [
         "run"
       ],
@@ -63,7 +78,6 @@
     },
     {
       "taskName": "Run: Benchmarks",
-      "command": "dotnet",
       "args": [
         "run",
         "-c",
@@ -72,33 +86,6 @@
       "options": {
         "cwd": "${workspaceRoot}/test/Microsoft.AspNetCore.Server.Kestrel.Performance/"
       }
-    },
-    {
-      "taskName": "Test: KestrelTests",
-      "isTestCommand": true,
-      "command": "dotnet",
-      "args": [
-        "test",
-        "-f",
-        "netcoreapp1.1"
-      ],
-      "options": {
-        "cwd": "${workspaceRoot}/test/Microsoft.AspNetCore.Server.KestrelTests"
-      },
-      "problemMatcher": "$msCompile"
-    },
-    {
-      "taskName": "Test: FunctionalTests",
-      "command": "dotnet",
-      "args": [
-        "test",
-        "-f",
-        "netcoreapp1.1"
-      ],
-      "options": {
-        "cwd": "${workspaceRoot}/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests"
-      },
-      "problemMatcher": "$msCompile"
     }
   ]
 }
diff --git a/src/Microsoft.AspNetCore.Server.Kestrel.Core/BadHttpRequestException.cs b/src/Microsoft.AspNetCore.Server.Kestrel.Core/BadHttpRequestException.cs
index 5a19ea4565..6bc10f460d 100644
--- a/src/Microsoft.AspNetCore.Server.Kestrel.Core/BadHttpRequestException.cs
+++ b/src/Microsoft.AspNetCore.Server.Kestrel.Core/BadHttpRequestException.cs
@@ -80,6 +80,15 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
                 case RequestRejectionReason.ConnectMethodRequired:
                     ex = new BadHttpRequestException("Method not allowed.", StatusCodes.Status405MethodNotAllowed, HttpMethod.Connect);
                     break;
+                case RequestRejectionReason.MissingHostHeader:
+                    ex = new BadHttpRequestException("Request is missing Host header.", StatusCodes.Status400BadRequest);
+                    break;
+                case RequestRejectionReason.MultipleHostHeaders:
+                    ex = new BadHttpRequestException("Multiple Host headers.", StatusCodes.Status400BadRequest);
+                    break;
+                case RequestRejectionReason.InvalidHostHeader:
+                    ex = new BadHttpRequestException("Invalid Host header.", StatusCodes.Status400BadRequest);
+                    break;
                 default:
                     ex = new BadHttpRequestException("Bad request.", StatusCodes.Status400BadRequest);
                     break;
@@ -116,6 +125,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
                 case RequestRejectionReason.LengthRequiredHttp10:
                     ex = new BadHttpRequestException($"{detail} request contains no Content-Length header", StatusCodes.Status400BadRequest);
                     break;
+                case RequestRejectionReason.InvalidHostHeader:
+                    ex = new BadHttpRequestException($"Invalid Host header: '{detail}'", StatusCodes.Status400BadRequest);
+                    break;
                 default:
                     ex = new BadHttpRequestException("Bad request.", StatusCodes.Status400BadRequest);
                     break;
diff --git a/src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/Frame.cs b/src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/Frame.cs
index 4d84a1c6d4..9dc9106e48 100644
--- a/src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/Frame.cs
+++ b/src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/Frame.cs
@@ -82,6 +82,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         private readonly FrameContext _frameContext;
         private readonly IHttpParser<FrameAdapter> _parser;
 
+        private HttpRequestTarget _requestTargetForm = HttpRequestTarget.Unknown;
+        private Uri _absoluteRequestTarget;
+
         public Frame(FrameContext frameContext)
         {
             _frameContext = frameContext;
@@ -141,6 +144,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         public string Path { get; set; }
         public string QueryString { get; set; }
         public string RawTarget { get; set; }
+
         public string HttpVersion
         {
             get
@@ -365,6 +369,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             Method = null;
             PathBase = null;
             Path = null;
+            RawTarget = null;
+            _requestTargetForm = HttpRequestTarget.Unknown;
+            _absoluteRequestTarget = null;
             QueryString = null;
             _httpVersion = Http.HttpVersion.Unknown;
             StatusCode = StatusCodes.Status200OK;
@@ -1266,6 +1273,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         {
             Debug.Assert(target[0] == ByteForwardSlash, "Should only be called when path starts with /");
 
+            _requestTargetForm = HttpRequestTarget.OriginForm;
+
             // URIs are always encoded/escaped to ASCII https://tools.ietf.org/html/rfc3986#page-11
             // Multibyte Internationalized Resource Identifiers (IRIs) are first converted to utf8;
             // then encoded/escaped to ASCII  https://www.ietf.org/rfc/rfc3987.txt "Mapping of IRIs to URIs"
@@ -1325,8 +1334,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 
         private void OnAuthorityFormTarget(HttpMethod method, Span<byte> target)
         {
-            // TODO Validate that target is a correct host[:port] string.
-            // Reject as 400 if not. This is just a quick scan for invalid characters
+            _requestTargetForm = HttpRequestTarget.AuthorityForm;
+
+            // This is not complete validation. It is just a quick scan for invalid characters
             // but doesn't check that the target fully matches the URI spec.
             for (var i = 0; i < target.Length; i++)
             {
@@ -1360,6 +1370,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 
         private void OnAsteriskFormTarget(HttpMethod method)
         {
+            _requestTargetForm = HttpRequestTarget.AsteriskForm;
+
             // The asterisk-form of request-target is only used for a server-wide
             // OPTIONS request (https://tools.ietf.org/html/rfc7231#section-4.3.7).
             if (method != HttpMethod.Options)
@@ -1374,6 +1386,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 
         private void OnAbsoluteFormTarget(Span<byte> target, Span<byte> query)
         {
+            _requestTargetForm = HttpRequestTarget.AbsoluteForm;
+
             // absolute-form
             // https://tools.ietf.org/html/rfc7230#section-5.3.2
 
@@ -1394,6 +1408,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
                 RejectRequestTarget(target);
             }
 
+            _absoluteRequestTarget = uri;
             Path = uri.LocalPath;
             // don't use uri.Query because we need the unescaped version
             QueryString = query.GetAsciiStringNonNullCharacters();
@@ -1420,5 +1435,62 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 
             FrameRequestHeaders.Append(name, valueString);
         }
+
+        protected void EnsureHostHeaderExists()
+        {
+            if (_httpVersion == Http.HttpVersion.Http10)
+            {
+                return;
+            }
+
+            // https://tools.ietf.org/html/rfc7230#section-5.4
+            // A server MUST respond with a 400 (Bad Request) status code to any
+            // HTTP/1.1 request message that lacks a Host header field and to any
+            // request message that contains more than one Host header field or a
+            // Host header field with an invalid field-value.
+
+            var host = FrameRequestHeaders.HeaderHost;
+            if (host.Count <= 0)
+            {
+                RejectRequest(RequestRejectionReason.MissingHostHeader);
+            }
+            else if (host.Count > 1)
+            {
+                RejectRequest(RequestRejectionReason.MultipleHostHeaders);
+            }
+            else if (_requestTargetForm == HttpRequestTarget.AuthorityForm)
+            {
+                if (!host.Equals(RawTarget))
+                {
+                    RejectRequest(RequestRejectionReason.InvalidHostHeader, host.ToString());
+                }
+            }
+            else if (_requestTargetForm == HttpRequestTarget.AbsoluteForm)
+            {
+                // If the target URI includes an authority component, then a
+                // client MUST send a field - value for Host that is identical to that
+                // authority component, excluding any userinfo subcomponent and its "@"
+                // delimiter.
+
+                // System.Uri doesn't not tell us if the port was in the original string or not.
+                // When IsDefaultPort = true, we will allow Host: with or without the default port
+                var authorityAndPort = _absoluteRequestTarget.Authority + ":" + _absoluteRequestTarget.Port;
+                if ((host != _absoluteRequestTarget.Authority || !_absoluteRequestTarget.IsDefaultPort)
+                    && host != authorityAndPort)
+                {
+                    RejectRequest(RequestRejectionReason.InvalidHostHeader, host.ToString());
+                }
+            }
+        }
+
+        private enum HttpRequestTarget
+        {
+            Unknown = -1,
+            // origin-form is the most common
+            OriginForm,
+            AbsoluteForm,
+            AuthorityForm,
+            AsteriskForm
+        }
     }
 }
diff --git a/src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/FrameOfT.cs b/src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/FrameOfT.cs
index 4073bc0837..b95a42c6a8 100644
--- a/src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/FrameOfT.cs
+++ b/src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/FrameOfT.cs
@@ -85,6 +85,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 
                     if (!_requestProcessingStopping)
                     {
+                        EnsureHostHeaderExists();
+
                         var messageBody = MessageBody.For(_httpVersion, FrameRequestHeaders, this);
                         _keepAlive = messageBody.RequestKeepAlive;
                         _upgrade = messageBody.RequestUpgrade;
diff --git a/src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/RequestRejectionReason.cs b/src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/RequestRejectionReason.cs
index e6b70b7551..ea03aab6fa 100644
--- a/src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/RequestRejectionReason.cs
+++ b/src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/RequestRejectionReason.cs
@@ -27,5 +27,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         LengthRequiredHttp10,
         OptionsMethodRequired,
         ConnectMethodRequired,
+        MissingHostHeader,
+        MultipleHostHeaders,
+        InvalidHostHeader,
     }
 }
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/FrameTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/FrameTests.cs
index f2928ac9c2..8ace3c7338 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/FrameTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/FrameTests.cs
@@ -533,7 +533,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
         {
             _frame.Start();
 
-            var data = Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\n\r\n");
+            var data = Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\nHost:\r\n\r\n");
             await _input.Writer.WriteAsync(data);
 
             var requestProcessingTask = _frame.StopAsync();
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/BadHttpRequestTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/BadHttpRequestTests.cs
index 4c59212c6c..d97289edd8 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/BadHttpRequestTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/BadHttpRequestTests.cs
@@ -67,7 +67,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
         public Task BadRequestIfMethodRequiresLengthButNoContentLengthOrTransferEncodingInRequest(string method)
         {
             return TestBadRequest(
-                $"{method} / HTTP/1.1\r\n\r\n",
+                $"{method} / HTTP/1.1\r\nHost:\r\n\r\n",
                 "411 Length Required",
                 $"{method} request contains no Content-Length or Transfer-Encoding header");
         }
@@ -89,7 +89,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
         public Task BadRequestIfContentLengthInvalid(string contentLength)
         {
             return TestBadRequest(
-                $"POST / HTTP/1.1\r\nContent-Length: {contentLength}\r\n\r\n",
+                $"POST / HTTP/1.1\r\nHost:\r\nContent-Length: {contentLength}\r\n\r\n",
                 "400 Bad Request",
                 $"Invalid content length: {contentLength}");
         }
@@ -106,6 +106,33 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 $"Allow: {allowedMethod}");
         }
 
+        [Fact]
+        public Task BadRequestIfHostHeaderMissing()
+        {
+            return TestBadRequest(
+                "GET / HTTP/1.1\r\n\r\n",
+                "400 Bad Request",
+                "Request is missing Host header.");
+        }
+
+        [Fact]
+        public Task BadRequestIfMultipleHostHeaders()
+        {
+            return TestBadRequest("GET / HTTP/1.1\r\nHost: localhost\r\nHost: localhost\r\n\r\n",
+                "400 Bad Request",
+                "Multiple Host headers.");
+        }
+
+        [Theory]
+        [MemberData(nameof(InvalidHostHeaderData))]
+        public Task BadRequestIfHostHeaderDoesNotMatchRequestTarget(string requestTarget, string host)
+        {
+            return TestBadRequest(
+                $"{requestTarget} HTTP/1.1\r\nHost: {host}\r\n\r\n",
+                "400 Bad Request",
+                $"Invalid Host header: '{host.Trim()}'");
+        }
+
         [Fact]
         public async Task BadRequestLogsAreNotHigherThanInformation()
         {
@@ -211,5 +238,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
         public static TheoryData<string> UnrecognizedHttpVersionData => HttpParsingData.UnrecognizedHttpVersionData;
 
         public static IEnumerable<object[]> InvalidRequestHeaderData => HttpParsingData.RequestHeaderInvalidData;
+
+        public static TheoryData<string,string> InvalidHostHeaderData => HttpParsingData.HostHeaderInvalidData;
     }
 }
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ChunkedRequestTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ChunkedRequestTests.cs
index be1718d76a..c6e8adbdb2 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ChunkedRequestTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ChunkedRequestTests.cs
@@ -66,6 +66,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "POST / HTTP/1.0",
+                        "Host:",
                         "Transfer-Encoding: chunked",
                         "",
                         "5", "Hello",
@@ -95,6 +96,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "POST / HTTP/1.0",
+                        "Host:",
                         "Transfer-Encoding: chunked",
                         "Connection: keep-alive",
                         "",
@@ -146,15 +148,18 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Content-Length: 5",
                         "",
                         "HelloPOST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: chunked",
                         "",
                         "C", "HelloChunked",
                         "0",
                         "",
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Content-Length: 7",
                         "",
                         "Goodbye");
@@ -225,6 +230,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
 
                 IEnumerable<string> sendSequence = new string[] {
                     "POST / HTTP/1.1",
+                    "Host:",
                     "Transfer-Encoding: chunked",
                     "",
                     "C",
@@ -236,6 +242,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     sendSequence = sendSequence.Concat(new string[] {
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: chunked",
                         "",
                         "C",
@@ -247,6 +254,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
 
                 sendSequence = sendSequence.Concat(new string[] {
                     "POST / HTTP/1.1",
+                    "Host:",
                     "Content-Length: 7",
                     "",
                     "Goodbye"
@@ -286,6 +294,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.SendAll(
                         "POST / HTTP/1.1",
+                        "Host:",
                         $"{transferEncodingHeaderLine}",
                         $"{headerLine}",
                         "",
@@ -327,6 +336,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.SendAll(
                         "POST / HTTP/1.1",
+                        "Host:",
                         $"{transferEncodingHeaderLine}",
                         $"{headerLine}",
                         "",
@@ -396,6 +406,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
 
                 IEnumerable<string> sendSequence = new string[] {
                     "POST / HTTP/1.1",
+                    "Host:",
                     "Transfer-Encoding: chunked",
                     "",
                     "C;hello there",
@@ -407,6 +418,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     sendSequence = sendSequence.Concat(new string[] {
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: chunked",
                         "",
                         "C;hello there",
@@ -418,6 +430,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
 
                 sendSequence = sendSequence.Concat(new string[] {
                     "POST / HTTP/1.1",
+                    "Host:",
                     "Content-Length: 7",
                     "",
                     "Goodbye"
@@ -459,6 +472,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.SendAll(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: chunked",
                         "",
                         "Cii");
@@ -502,6 +516,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.SendAll(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: chunked",
                         "",
                         "C",
@@ -535,6 +550,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.SendAll(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: not-chunked",
                         "",
                         "C",
@@ -557,6 +573,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.SendAll(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: not-chunked",
                         "Content-Length: 22",
                         "",
@@ -579,6 +596,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.SendAll(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: chunked, not-chunked",
                         "",
                         "C",
@@ -601,6 +619,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.SendAll(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: chunked, not-chunked",
                         "Content-Length: 22",
                         "",
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ChunkedResponseTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ChunkedResponseTests.cs
index d68283a1ab..dc953808ce 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ChunkedResponseTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ChunkedResponseTests.cs
@@ -41,6 +41,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveEnd(
@@ -104,6 +105,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host: ",
                         "Connection: close",
                         "",
                         "");
@@ -141,6 +143,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host: ",
                         "",
                         "");
                     await connection.ReceiveEnd(
@@ -178,6 +181,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host: ",
                         "",
                         "");
                     await connection.ReceiveEnd(
@@ -218,6 +222,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host: ",
                         "",
                         "");
 
@@ -256,6 +261,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host: ",
                         "",
                         "");
                     await connection.ReceiveEnd(
@@ -289,6 +295,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                     // client closing the connection.
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host: ",
                         "",
                         "");
                     await connection.ReceiveForcedEnd(
@@ -321,6 +328,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                     // SendEnd is not called, so it isn't the client closing the connection.
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host: ",
                         "",
                         "");
 
@@ -358,6 +366,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host: ",
                         "",
                         "");
                     await connection.Receive(
@@ -401,6 +410,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host: ",
                         "",
                         "");
                     await connection.ReceiveEnd(
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/DefaultHeaderTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/DefaultHeaderTests.cs
index 91ff1816cf..c9c1a94ae6 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/DefaultHeaderTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/DefaultHeaderTests.cs
@@ -24,6 +24,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "GET / HTTP/1.0",
                         "",
@@ -46,4 +47,4 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/EventSourceTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/EventSourceTests.cs
index f692537ea7..e2f40011a7 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/EventSourceTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/EventSourceTests.cs
@@ -40,6 +40,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 using (var connection = server.CreateConnection())
                 {
                     await connection.SendAll("GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "")
                         .TimeoutAfter(TimeSpan.FromSeconds(10));
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/HttpsTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/HttpsTests.cs
index dc075abf9e..391441ed5b 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/HttpsTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/HttpsTests.cs
@@ -137,7 +137,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                         enabledSslProtocols: SslProtocols.Tls11 | SslProtocols.Tls12,
                         checkCertificateRevocation: false);
 
-                    var request = Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\n\r\n");
+                    var request = Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\nHost:\r\n\r\n");
                     await sslStream.WriteAsync(request, 0, request.Length);
                     await sslStream.ReadAsync(new byte[32], 0, 32);
                 }
@@ -187,7 +187,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                         enabledSslProtocols: SslProtocols.Tls11 | SslProtocols.Tls12,
                         checkCertificateRevocation: false);
 
-                    var request = Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\n\r\n");
+                    var request = Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\nHost:\r\n\r\n");
                     await sslStream.WriteAsync(request, 0, request.Length);
                     await sslStream.ReadAsync(new byte[32], 0, 32);
                 }
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/KeepAliveTimeoutTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/KeepAliveTimeoutTests.cs
index 01b070dac6..64dd29e7cc 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/KeepAliveTimeoutTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/KeepAliveTimeoutTests.cs
@@ -57,6 +57,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             {
                 await connection.Send(
                     "GET / HTTP/1.1",
+                    "Host:",
                     "",
                     "");
                 await ReceiveResponse(connection);
@@ -72,6 +73,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await Task.Delay(ShortDelay);
@@ -93,6 +95,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
 
                 await connection.Send(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: chunked",
                         "",
                         "");
@@ -120,6 +123,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             {
                 await connection.Send(
                     "GET /longrunning HTTP/1.1",
+                    "Host:",
                     "",
                     "");
                 cts.CancelAfter(LongDelay);
@@ -133,6 +137,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
 
                 await connection.Send(
                     "GET / HTTP/1.1",
+                    "Host:",
                     "",
                     "");
                 await ReceiveResponse(connection);
@@ -154,6 +159,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             {
                 await connection.Send(
                     "GET /upgrade HTTP/1.1",
+                    "Host:",
                     "",
                     "");
                 await connection.Receive(
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/MaxRequestBufferSizeTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/MaxRequestBufferSizeTests.cs
index 6452832639..2b9c7dcd46 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/MaxRequestBufferSizeTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/MaxRequestBufferSizeTests.cs
@@ -89,8 +89,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             // Initialize data with random bytes
             (new Random()).NextBytes(data);
 
-            var startReadingRequestBody = new ManualResetEvent(false);
-            var clientFinishedSendingRequestBody = new ManualResetEvent(false);
+            var startReadingRequestBody = new TaskCompletionSource<object>();
+            var clientFinishedSendingRequestBody = new TaskCompletionSource<object>();
             var lastBytesWritten = DateTime.MaxValue;
 
             using (var host = StartWebHost(maxRequestBufferSize, data, connectionAdapter, startReadingRequestBody, clientFinishedSendingRequestBody))
@@ -114,7 +114,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                         }
 
                         Assert.Equal(data.Length, bytesWritten);
-                        clientFinishedSendingRequestBody.Set();
+                        clientFinishedSendingRequestBody.TrySetResult(null);
                     };
 
                     var sendTask = sendFunc();
@@ -149,7 +149,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                         Assert.InRange(bytesWritten, minimumExpectedBytesWritten, maximumExpectedBytesWritten);
 
                         // Tell server to start reading request body
-                        startReadingRequestBody.Set();
+                        startReadingRequestBody.TrySetResult(null);
 
                         // Wait for sendTask to finish sending the remaining bytes
                         await sendTask;
@@ -160,7 +160,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                         await sendTask;
 
                         // Tell server to start reading request body
-                        startReadingRequestBody.Set();
+                        startReadingRequestBody.TrySetResult(null);
                     }
 
                     using (var reader = new StreamReader(stream, Encoding.ASCII))
@@ -181,8 +181,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             var bytesWrittenPollingInterval = TimeSpan.FromMilliseconds(bytesWrittenTimeout.TotalMilliseconds / 10);
             var maxSendSize = 4096;
 
-            var startReadingRequestBody = new ManualResetEvent(false);
-            var clientFinishedSendingRequestBody = new ManualResetEvent(false);
+            var startReadingRequestBody = new TaskCompletionSource<object>();
+            var clientFinishedSendingRequestBody = new TaskCompletionSource<object>();
             var lastBytesWritten = DateTime.MaxValue;
 
             using (var host = StartWebHost(16 * 1024, data, false, startReadingRequestBody, clientFinishedSendingRequestBody))
@@ -205,7 +205,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                             lastBytesWritten = DateTime.Now;
                         }
 
-                        clientFinishedSendingRequestBody.Set();
+                        clientFinishedSendingRequestBody.TrySetResult(null);
                     };
 
                     var ignore = sendFunc();
@@ -244,8 +244,11 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             }
         }
 
-        private static IWebHost StartWebHost(long? maxRequestBufferSize, byte[] expectedBody, bool useConnectionAdapter, ManualResetEvent startReadingRequestBody,
-            ManualResetEvent clientFinishedSendingRequestBody)
+        private static IWebHost StartWebHost(long? maxRequestBufferSize, 
+            byte[] expectedBody, 
+            bool useConnectionAdapter, 
+            TaskCompletionSource<object> startReadingRequestBody,
+            TaskCompletionSource<object> clientFinishedSendingRequestBody)
         {
             var host = new WebHostBuilder()
                 .UseKestrel(options =>
@@ -275,7 +278,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 .UseContentRoot(Directory.GetCurrentDirectory())
                 .Configure(app => app.Run(async context =>
                 {
-                    startReadingRequestBody.WaitOne();
+                    await startReadingRequestBody.Task.TimeoutAfter(TimeSpan.FromSeconds(30));
 
                     var buffer = new byte[expectedBody.Length];
                     var bytesRead = 0;
@@ -284,7 +287,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                         bytesRead += await context.Request.Body.ReadAsync(buffer, bytesRead, buffer.Length - bytesRead);
                     }
 
-                    clientFinishedSendingRequestBody.WaitOne();
+                    await clientFinishedSendingRequestBody.Task.TimeoutAfter(TimeSpan.FromSeconds(30));
 
                     // Verify client didn't send extra bytes
                     if (context.Request.Body.ReadByte() != -1)
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/MaxRequestLineSizeTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/MaxRequestLineSizeTests.cs
index 8e3dd5d22e..0ac7785d11 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/MaxRequestLineSizeTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/MaxRequestLineSizeTests.cs
@@ -12,18 +12,18 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
     public class MaxRequestLineSizeTests
     {
         [Theory]
-        [InlineData("GET / HTTP/1.1\r\n\r\n", 16)]
-        [InlineData("GET / HTTP/1.1\r\n\r\n", 17)]
-        [InlineData("GET / HTTP/1.1\r\n\r\n", 137)]
-        [InlineData("POST /abc/de HTTP/1.1\r\nContent-Length: 0\r\n\r\n", 23)]
-        [InlineData("POST /abc/de HTTP/1.1\r\nContent-Length: 0\r\n\r\n", 24)]
-        [InlineData("POST /abc/de HTTP/1.1\r\nContent-Length: 0\r\n\r\n", 287)]
-        [InlineData("PUT /abc/de?f=ghi HTTP/1.1\r\nContent-Length: 0\r\n\r\n", 28)]
-        [InlineData("PUT /abc/de?f=ghi HTTP/1.1\r\nContent-Length: 0\r\n\r\n", 29)]
-        [InlineData("PUT /abc/de?f=ghi HTTP/1.1\r\nContent-Length: 0\r\n\r\n", 589)]
-        [InlineData("DELETE /a%20b%20c/d%20e?f=ghi HTTP/1.1\r\n\r\n", 40)]
-        [InlineData("DELETE /a%20b%20c/d%20e?f=ghi HTTP/1.1\r\n\r\n", 41)]
-        [InlineData("DELETE /a%20b%20c/d%20e?f=ghi HTTP/1.1\r\n\r\n", 1027)]
+        [InlineData("GET / HTTP/1.1\r\nHost:\r\n\r\n", 16)]
+        [InlineData("GET / HTTP/1.1\r\nHost:\r\n\r\n", 17)]
+        [InlineData("GET / HTTP/1.1\r\nHost:\r\n\r\n", 137)]
+        [InlineData("POST /abc/de HTTP/1.1\r\nHost:\r\nContent-Length: 0\r\n\r\n", 23)]
+        [InlineData("POST /abc/de HTTP/1.1\r\nHost:\r\nContent-Length: 0\r\n\r\n", 24)]
+        [InlineData("POST /abc/de HTTP/1.1\r\nHost:\r\nContent-Length: 0\r\n\r\n", 287)]
+        [InlineData("PUT /abc/de?f=ghi HTTP/1.1\r\nHost:\r\nContent-Length: 0\r\n\r\n", 28)]
+        [InlineData("PUT /abc/de?f=ghi HTTP/1.1\r\nHost:\r\nContent-Length: 0\r\n\r\n", 29)]
+        [InlineData("PUT /abc/de?f=ghi HTTP/1.1\r\nHost:\r\nContent-Length: 0\r\n\r\n", 589)]
+        [InlineData("DELETE /a%20b%20c/d%20e?f=ghi HTTP/1.1\r\nHost:\r\n\r\n", 40)]
+        [InlineData("DELETE /a%20b%20c/d%20e?f=ghi HTTP/1.1\r\nHost:\r\n\r\n", 41)]
+        [InlineData("DELETE /a%20b%20c/d%20e?f=ghi HTTP/1.1\r\nHost:\r\n\r\n", 1027)]
         public async Task ServerAcceptsRequestLineWithinLimit(string request, int limit)
         {
             using (var server = CreateServer(limit))
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests.csproj b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests.csproj
index 21a47f7c0d..cd10cab0df 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests.csproj
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests.csproj
@@ -8,6 +8,7 @@
     <PlatformTarget Condition="'$(TargetFramework)' == 'net46'">x64</PlatformTarget>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
     <GenerateBindingRedirectsOutputType>true</GenerateBindingRedirectsOutputType>
+    <ServerGarbageCollection>true</ServerGarbageCollection>
 
     <!--
       Workaround for "Explicit RID still required for .NET Framework test projects" (https://github.com/dotnet/sdk/issues/909).
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestHeaderLimitsTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestHeaderLimitsTests.cs
index d5087cc23f..375e92c255 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestHeaderLimitsTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestHeaderLimitsTests.cs
@@ -125,9 +125,13 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
 
         private static string MakeHeaders(int count)
         {
-            return string.Join("", Enumerable
-                .Range(0, count)
-                .Select(i => $"Header-{i}: value{i}\r\n"));
+            const string host = "Host:\r\n";
+            if (count <= 1) return host;
+
+            return string.Join("", new[] { host }
+                .Concat(Enumerable
+                .Range(0, count -1)
+                .Select(i => $"Header-{i}: value{i}\r\n")));
         }
 
         private TestServer CreateServer(int? maxRequestHeaderCount = null, int? maxRequestHeadersTotalSize = null)
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestHeadersTimeoutTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestHeadersTimeoutTests.cs
index 4514ace0d2..9ed7f7680f 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestHeadersTimeoutTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestHeadersTimeoutTests.cs
@@ -25,9 +25,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             {
                 var tasks = new[]
                 {
-                    ConnectionAbortedWhenRequestHeadersNotReceivedInTime(server, ""),
-                    ConnectionAbortedWhenRequestHeadersNotReceivedInTime(server, "Content-Length: 1\r\n"),
-                    ConnectionAbortedWhenRequestHeadersNotReceivedInTime(server, "Content-Length: 1\r\n\r"),
+                    ConnectionAbortedWhenRequestHeadersNotReceivedInTime(server, "Host:\r\n"),
+                    ConnectionAbortedWhenRequestHeadersNotReceivedInTime(server, "Host:\r\nContent-Length: 1\r\n"),
+                    ConnectionAbortedWhenRequestHeadersNotReceivedInTime(server, "Host:\r\nContent-Length: 1\r\n\r"),
                     RequestHeadersTimeoutCanceledAfterHeadersReceived(server),
                     ConnectionAbortedWhenRequestLineNotReceivedInTime(server, "P"),
                     ConnectionAbortedWhenRequestLineNotReceivedInTime(server, "POST / HTTP/1.1\r"),
@@ -55,6 +55,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             {
                 await connection.Send(
                     "POST / HTTP/1.1",
+                    "Host:",
                     "Content-Length: 1",
                     "",
                     "");
@@ -80,7 +81,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             {
                 await Assert.ThrowsAsync<IOException>(async () =>
                 {
-                    foreach (var ch in "POST / HTTP/1.1\r\n\r\n")
+                    foreach (var ch in "POST / HTTP/1.1\r\nHost:\r\n\r\n")
                     {
                         await connection.Send(ch.ToString());
                         await Task.Delay(ShortDelay);
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestTargetProcessingTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestTargetProcessingTests.cs
index 3d9a55b9f6..4ebb7ce571 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestTargetProcessingTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestTargetProcessingTests.cs
@@ -33,6 +33,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET /%41%CC%8A/A/../B/%41%CC%8A HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveEnd(
@@ -77,6 +78,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         $"GET {requestTarget} HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveEnd(
@@ -109,8 +111,13 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             {
                 using (var connection = server.CreateConnection())
                 {
+                    var host = method == HttpMethod.Connect 
+                        ? requestTarget 
+                        : string.Empty;
+
                     await connection.Send(
                         $"{HttpUtilities.MethodToString(method)} {requestTarget} HTTP/1.1",
+                        $"Host: {host}",
                         "",
                         "");
                     await connection.ReceiveEnd(
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestTests.cs
index abb9dace50..6b9d901880 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestTests.cs
@@ -242,7 +242,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 using (var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
                 {
                     socket.Connect(new IPEndPoint(IPAddress.Loopback, host.GetPort()));
-                    socket.Send(Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\nConnection: keep-alive, upgrade\r\n\r\n"));
+                    socket.Send(Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\nHost:\r\nConnection: keep-alive, upgrade\r\n\r\n"));
                     socket.Send(Encoding.ASCII.GetBytes("abc"));
 
                     while (socket.Receive(new byte[1024]) > 0) ;
@@ -357,7 +357,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 using (var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
                 {
                     socket.Connect(new IPEndPoint(IPAddress.Loopback, host.GetPort()));
-                    socket.Send(Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\n\r\n"));
+                    socket.Send(Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\nHost:\r\n\r\n"));
 
                     // Wait until request is done being processed
                     await requestDone.WaitAsync(TimeSpan.FromSeconds(10));
@@ -417,7 +417,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 using (var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
                 {
                     socket.Connect(new IPEndPoint(IPAddress.Loopback, host.GetPort()));
-                    socket.Send(Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\n\r\n"));
+                    socket.Send(Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\nHost:\r\n\r\n"));
 
                     // Wait until connection is established
                     await requestStarted.WaitAsync(TimeSpan.FromSeconds(10));
@@ -470,7 +470,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     socket.Connect(new IPEndPoint(IPAddress.Loopback, host.GetPort()));
                     socket.LingerState = new LingerOption(true, 0);
-                    socket.Send(Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\nContent-Length: 1\r\n\r\n"));
+                    socket.Send(Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\nHost:\r\nContent-Length: 1\r\n\r\n"));
                     Assert.True(await requestStarted.WaitAsync(_semaphoreWaitTimeout));
                 }
 
@@ -505,7 +505,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 using (var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
                 {
                     socket.Connect(new IPEndPoint(IPAddress.Loopback, host.GetPort()));
-                    socket.Send(Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\n\r\n"));
+                    socket.Send(Encoding.ASCII.GetBytes("GET / HTTP/1.1\r\nHost:\r\n\r\n"));
                     await appStarted.WaitAsync();
                     socket.Shutdown(SocketShutdown.Send);
                     await requestAborted.WaitAsync().TimeoutAfter(TimeSpan.FromSeconds(10));
@@ -534,13 +534,11 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
         {
             var pathTcs = new TaskCompletionSource<PathString>();
             var rawTargetTcs = new TaskCompletionSource<string>();
-            var hostTcs = new TaskCompletionSource<HostString>();
             var queryTcs = new TaskCompletionSource<IQueryCollection>();
 
             using (var server = new TestServer(async context =>
                  {
                      pathTcs.TrySetResult(context.Request.Path);
-                     hostTcs.TrySetResult(context.Request.Host);
                      queryTcs.TrySetResult(context.Request.Query);
                      rawTargetTcs.TrySetResult(context.Features.Get<IHttpRequestFeature>().RawTarget);
                      await context.Response.WriteAsync("Done");
@@ -548,10 +546,17 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             {
                 using (var connection = server.CreateConnection())
                 {
+                    var requestTarget = new Uri(requestUrl, UriKind.Absolute);
+                    var host = requestTarget.Authority;
+                    if (!requestTarget.IsDefaultPort)
+                    {
+                        host += ":" + requestTarget.Port;
+                    }
+
                     await connection.Send(
                         $"GET {requestUrl} HTTP/1.1",
                         "Content-Length: 0",
-                        "Host: localhost",
+                        $"Host: {host}",
                         "",
                         "");
 
@@ -563,10 +568,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                         "Done")
                         .TimeoutAfter(TimeSpan.FromSeconds(10));
 
-                    await Task.WhenAll(pathTcs.Task, rawTargetTcs.Task, hostTcs.Task, queryTcs.Task).TimeoutAfter(TimeSpan.FromSeconds(30));
+                    await Task.WhenAll(pathTcs.Task, rawTargetTcs.Task, queryTcs.Task).TimeoutAfter(TimeSpan.FromSeconds(30));
                     Assert.Equal(new PathString(expectedPath), pathTcs.Task.Result);
                     Assert.Equal(requestUrl, rawTargetTcs.Task.Result);
-                    Assert.Equal("localhost", hostTcs.Task.Result.ToString());
                     if (queryValue == null)
                     {
                         Assert.False(queryTcs.Task.Result.ContainsKey("q"));
@@ -626,6 +630,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                     for (var i = 0; i < iterations; i++)
                     {
                         await connection.Send("GET / HTTP/1.1",
+                            "Host:",
                             "",
                             "");
 
@@ -657,8 +662,10 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "GET / HTTP/1.1",
+                        "Host:",
                         "Connection: close",
                         "Content-Length: 7",
                         "",
@@ -862,6 +869,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Expect: 100-continue",
                         "Connection: close",
                         "Content-Length: 11",
@@ -901,6 +909,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                     // https://github.com/aspnet/KestrelHttpServer/issues/1104 is not regressing.
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "Connection: close",
                         "",
                         "");
@@ -917,6 +926,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.0",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveForcedEnd(
@@ -950,6 +960,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Content-Length: 7");
                     connection.Shutdown(SocketShutdown.Send);
                     await connection.ReceiveForcedEnd();
@@ -1008,9 +1019,11 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                     // Never send the body so CopyToAsync always fails.
                     await connection.Send(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Content-Length: 5",
                         "",
                         "HelloPOST / HTTP/1.1",
+                        "Host:",
                         "Content-Length: 5",
                         "",
                         "");
@@ -1062,8 +1075,10 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveEnd(
@@ -1107,6 +1122,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "Connection: Upgrade",
                         "",
                         message);
@@ -1163,8 +1179,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 using (var connection = server.CreateConnection())
                 {
                     var requestData =
-                        Enumerable.Repeat("GET / HTTP/1.1\r\n", loopCount)
-                            .Concat(new[] { "GET / HTTP/1.1\r\nContent-Length: 7\r\nConnection: close\r\n\r\nGoodbye" });
+                        Enumerable.Repeat("GET / HTTP/1.1\r\nHost:\r\n", loopCount)
+                            .Concat(new[] { "GET / HTTP/1.1\r\nHost:\r\nContent-Length: 7\r\nConnection: close\r\n\r\nGoodbye" });
 
                     var response = string.Join("\r\n", new string[] {
                         "HTTP/1.1 200 OK",
@@ -1197,6 +1213,24 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             }
         }
 
+        [Theory]
+        [MemberData(nameof(HostHeaderData))]
+        public async Task MatchesValidRequestTargetAndHostHeader(string request, string hostHeader)
+        {
+            using (var server = new TestServer(context => Task.CompletedTask))
+            {
+                using (var connection = server.CreateConnection())
+                {
+                    await connection.Send($"{request} HTTP/1.1",
+                        $"Host: {hostHeader}",
+                        "",
+                        "");
+
+                    await connection.Receive("HTTP/1.1 200 OK");
+                }
+            }
+        }
+
         private async Task TestRemoteIPAddress(string registerAddress, string requestAddress, string expectAddress)
         {
             var builder = new WebHostBuilder()
@@ -1233,5 +1267,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 Assert.NotEmpty(facts["RemotePort"].Value<string>());
             }
         }
+
+        public static TheoryData<string, string> HostHeaderData => HttpParsingData.HostHeaderData;
     }
 }
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ResponseTests.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ResponseTests.cs
index 02b2590e16..7437ad005f 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ResponseTests.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ResponseTests.cs
@@ -326,6 +326,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                     {
                         await connection.Send(
                             "POST / HTTP/1.1",
+                            "Host:",
                             "Transfer-Encoding: chunked",
                             "",
                             "gg");
@@ -360,6 +361,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: chunked",
                         "",
                         "gg");
@@ -389,6 +391,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -423,6 +426,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -446,6 +450,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "HEAD / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -478,6 +483,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "HEAD / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -515,6 +521,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -524,7 +531,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                         "",
                         "hello,");
 
-                    await connection.WaitForConnectionClose();
+                    await connection.WaitForConnectionClose().TimeoutAfter(TimeSpan.FromSeconds(30));
                 }
             }
 
@@ -554,6 +561,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveForcedEnd(
@@ -589,6 +597,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveForcedEnd(
@@ -624,6 +633,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveForcedEnd(
@@ -664,6 +674,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
 
@@ -718,6 +729,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -757,8 +769,10 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -801,6 +815,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -836,6 +851,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -872,6 +888,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -900,6 +917,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "HEAD / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -928,6 +946,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "HEAD / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -959,6 +978,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "HEAD / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -990,6 +1010,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -1033,17 +1054,18 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
 
                     requestStarted.Wait();
                     connection.Shutdown(SocketShutdown.Send);
-                    await connection.WaitForConnectionClose();
+                    await connection.WaitForConnectionClose().TimeoutAfter(TimeSpan.FromSeconds(30));
                 }
 
                 connectionClosed.Set();
 
-                await tcs.Task;
+                await tcs.Task.TimeoutAfter(TimeSpan.FromSeconds(30));
             }
         }
 
@@ -1073,10 +1095,11 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: chunked",
                         "",
                         "gg");
-                    await responseWritten.WaitAsync();
+                    await responseWritten.WaitAsync().TimeoutAfter(TimeSpan.FromSeconds(30));
                     await connection.ReceiveEnd(
                         "HTTP/1.1 400 Bad Request",
                         $"Date: {server.Context.DateHeaderValue}",
@@ -1104,6 +1127,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveForcedEnd(
@@ -1151,6 +1175,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveForcedEnd(
@@ -1197,6 +1222,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -1209,6 +1235,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                     // Make sure connection was kept open
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveEnd(
@@ -1245,6 +1272,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -1286,6 +1314,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -1327,6 +1356,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -1367,6 +1397,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.Receive(
@@ -1397,6 +1428,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Content-Length: 1",
                         "",
                         "");
@@ -1430,6 +1462,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: chunked",
                         "",
                         "gg");
@@ -1460,6 +1493,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Transfer-Encoding: chunked",
                         "Expect: 100-continue",
                         "",
@@ -1508,6 +1542,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Content-Length: 2",
                         "Expect: 100-continue",
                         "",
@@ -1578,6 +1613,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "GET / HTTP/1.0",
                         "Connection: keep-alive",
@@ -1613,6 +1649,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "Connection: close",
                         "",
                         "");
@@ -1654,6 +1691,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "HEAD / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveEnd(
@@ -1687,15 +1725,19 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Content-Length: 3",
                         "",
                         "204POST / HTTP/1.1",
+                        "Host:",
                         "Content-Length: 3",
                         "",
                         "205POST / HTTP/1.1",
+                        "Host:",
                         "Content-Length: 3",
                         "",
                         "304POST / HTTP/1.1",
+                        "Host:",
                         "Content-Length: 3",
                         "",
                         "200");
@@ -1736,6 +1778,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveForcedEnd(
@@ -1792,8 +1835,10 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "GET / HTTP/1.1",
+                        "Host:",
                         "Connection: close",
                         "",
                         "");
@@ -1850,8 +1895,10 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveEnd(
@@ -1909,6 +1956,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveForcedEnd(
@@ -1955,6 +2003,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveForcedEnd(
@@ -1999,6 +2048,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveForcedEnd(
@@ -2061,6 +2111,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "POST / HTTP/1.1",
+                        "Host:",
                         "Content-Length: 5",
                         "",
                         "Hello");
@@ -2166,8 +2217,10 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveEnd(
@@ -2217,6 +2270,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveEnd(
@@ -2268,6 +2322,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     await connection.Send(
                         "GET / HTTP/1.1",
+                        "Host:",
                         "",
                         "");
                     await connection.ReceiveEnd(
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/TestServer.cs b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/TestServer.cs
index 9a6681d7af..9c67ff053b 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/TestServer.cs
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/TestServer.cs
@@ -57,9 +57,12 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             }
             catch
             {
-                _transport.UnbindAsync().Wait();
-                _transport.StopAsync().Wait();
-                _transport = null;
+                if (_transport != null)
+                {
+                    _transport.UnbindAsync().Wait();
+                    _transport.StopAsync().Wait();
+                    _transport = null;
+                }
                 throw;
             }
         }
diff --git a/test/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Tests/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Tests.csproj b/test/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Tests/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Tests.csproj
index fb84173f97..6b7f36cfc6 100644
--- a/test/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Tests/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Tests.csproj
+++ b/test/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Tests/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.Tests.csproj
@@ -7,6 +7,7 @@
     <TargetFrameworks Condition=" '$(OS)' != 'Windows_NT' ">netcoreapp2.0</TargetFrameworks>
     <PlatformTarget Condition="'$(TargetFramework)' == 'net46'">x64</PlatformTarget>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <ServerGarbageCollection>true</ServerGarbageCollection>
 
     <!--
       Workaround for "Explicit RID still required for .NET Framework test projects" (https://github.com/dotnet/sdk/issues/909).
diff --git a/test/shared/HttpParsingData.cs b/test/shared/HttpParsingData.cs
index d3774bfd91..658fad2528 100644
--- a/test/shared/HttpParsingData.cs
+++ b/test/shared/HttpParsingData.cs
@@ -427,5 +427,58 @@ namespace Microsoft.AspNetCore.Testing
             new[] { "Header-1: value1\r\nHeader-2: value2\r\n\r ", @"Invalid request headers: missing final CRLF in header fields."  },
             new[] { "Header-1: value1\r\nHeader-2: value2\r\n\r \n", @"Invalid request headers: missing final CRLF in header fields." },
         };
+
+        public static TheoryData<string, string> HostHeaderData
+            => new TheoryData<string, string>
+                {
+                    { "OPTIONS *", "" },
+                    { "GET /pub/WWW/", "" },
+                    { "GET /pub/WWW/", "   " },
+                    { "GET /pub/WWW/", "www.example.org" },
+                    { "GET http://localhost/", "localhost" },
+                    { "GET http://localhost:80/", "localhost:80" },
+                    { "GET https://localhost/", "localhost" },
+                    { "GET https://localhost:443/", "localhost:443" },
+                    { "CONNECT asp.net:80", "asp.net:80" },
+                    { "CONNECT asp.net:443", "asp.net:443" },
+                };
+
+        public static TheoryData<string, string> HostHeaderInvalidData
+        {
+            get
+            {
+                // see https://tools.ietf.org/html/rfc7230#section-5.4
+                var invalidHostValues = new[] {
+                    "",
+                    "   ",
+                    "contoso.com:4000",
+                    "contoso.com/",
+                    "not-contoso.com",
+                    "user@password:contoso.com",
+                    "user@contoso.com",
+                    "http://contoso.com/",
+                    "http://contoso.com"
+                };
+
+                var data = new TheoryData<string, string>();
+
+                foreach (var host in invalidHostValues)
+                {
+                    // absolute form
+                    // expected: GET http://contoso.com/ => Host: contoso.com
+                    data.Add("GET http://contoso.com/", host);
+
+                    // authority-form
+                    // expected: CONNECT contoso.com => Host: contoso.com
+                    data.Add("CONNECT contoso.com", host);
+                }
+
+                // port mismatch when target contains port
+                data.Add("GET https://contoso.com:443/", "contoso.com:5000");
+                data.Add("CONNECT contoso.com:443", "contoso.com:5000");
+
+                return data;
+            }
+        }
     }
 }