diff --git a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/HttpCompliance.java b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/HttpCompliance.java
index 8e0a47d6924..1b9a20b9846 100644
--- a/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/HttpCompliance.java
+++ b/jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/HttpCompliance.java
@@ -117,7 +117,14 @@ public final class HttpCompliance implements ComplianceViolation.Mode
          * should reject a request if the Host headers contains an invalid / unsafe authority.
          * A deployment may include this violation to allow unsafe host headesr on a received request.
          */
-        UNSAFE_HOST_HEADER("https://www.rfc-editor.org/rfc/rfc7230#section-2.7.1", "Invalid Authority");
+        UNSAFE_HOST_HEADER("https://www.rfc-editor.org/rfc/rfc7230#section-2.7.1", "Invalid Authority"),
+
+        /**
+         * Since <a href="https://www.rfc-editor.org/rfc/rfc7230#section-5.4">RFC 7230: Section 5.4</a>, the HTTP protocol
+         * must reject a request if the target URI has an authority that is different than a provided Host header.
+         * A deployment may include this violation to allow different values on the target URI and the Host header on a received request.
+         */
+        MISMATCHED_AUTHORITY("https://www.rfc-editor.org/rfc/rfc7230#section-5.4", "Mismatched Authority");
 
         private final String url;
         private final String description;
@@ -162,7 +169,11 @@ public final class HttpCompliance implements ComplianceViolation.Mode
      * The HttpCompliance mode that supports <a href="https://tools.ietf.org/html/rfc2616">RFC 7230</a>
      * with only the violations that differ from {@link #RFC7230}.
      */
-    public static final HttpCompliance RFC2616 = new HttpCompliance("RFC2616", of(Violation.HTTP_0_9, Violation.MULTILINE_FIELD_VALUE));
+    public static final HttpCompliance RFC2616 = new HttpCompliance("RFC2616", of(
+        Violation.HTTP_0_9,
+        Violation.MULTILINE_FIELD_VALUE,
+        Violation.MISMATCHED_AUTHORITY
+    ));
 
     /**
      * A legacy HttpCompliance mode that allows all violations except case-insensitive methods.
diff --git a/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/HttpParserTest.java b/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/HttpParserTest.java
index c97d5cbb798..ad48badb429 100644
--- a/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/HttpParserTest.java
+++ b/jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/HttpParserTest.java
@@ -42,7 +42,6 @@ import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.is;
-import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.nullValue;
 import static org.hamcrest.Matchers.startsWith;
 import static org.junit.jupiter.api.Assertions.assertEquals;
diff --git a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/internal/HttpConnection.java b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/internal/HttpConnection.java
index f1a86e1e774..41c1ed65c02 100644
--- a/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/internal/HttpConnection.java
+++ b/jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/internal/HttpConnection.java
@@ -75,6 +75,7 @@ import org.eclipse.jetty.util.thread.Invocable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import static org.eclipse.jetty.http.HttpCompliance.Violation.MISMATCHED_AUTHORITY;
 import static org.eclipse.jetty.http.HttpStatus.INTERNAL_SERVER_ERROR_500;
 
 /**
@@ -359,6 +360,30 @@ public class HttpConnection extends AbstractConnection implements Runnable, Writ
         _useOutputDirectByteBuffers = useOutputDirectByteBuffers;
     }
 
+    protected void onComplianceViolation(ComplianceViolation.Mode mode, ComplianceViolation violation, String details)
+    {
+        //TODO configure this somewhere else
+        //TODO what about cookie compliance
+        //TODO what about http2 & 3
+        //TODO test this in core
+        if (isRecordHttpComplianceViolations())
+        {
+            HttpStreamOverHTTP1 stream = _stream.get();
+            if (stream != null)
+            {
+                if (stream._complianceViolations == null)
+                {
+                    stream._complianceViolations = new ArrayList<>();
+                }
+                String record = String.format("%s (see %s) in mode %s for %s in %s",
+                    violation.getDescription(), violation.getURL(), mode, details, HttpConnection.this);
+                stream._complianceViolations.add(record);
+                if (LOG.isDebugEnabled())
+                    LOG.debug(record);
+            }
+        }
+    }
+
     @Override
     public ByteBuffer onUpgradeFrom()
     {
@@ -1086,26 +1111,7 @@ public class HttpConnection extends AbstractConnection implements Runnable, Writ
         @Override
         public void onComplianceViolation(ComplianceViolation.Mode mode, ComplianceViolation violation, String details)
         {
-            //TODO configure this somewhere else
-            //TODO what about cookie compliance
-            //TODO what about http2 & 3
-            //TODO test this in core
-            if (isRecordHttpComplianceViolations())
-            {
-                HttpStreamOverHTTP1 stream = _stream.get();
-                if (stream != null)
-                {
-                    if (stream._complianceViolations == null)
-                    {
-                        stream._complianceViolations = new ArrayList<>();
-                    }
-                    String record = String.format("%s (see %s) in mode %s for %s in %s",
-                        violation.getDescription(), violation.getURL(), mode, details, HttpConnection.this);
-                    stream._complianceViolations.add(record);
-                    if (LOG.isDebugEnabled())
-                        LOG.debug(record);
-                }
-            }
+            HttpConnection.this.onComplianceViolation(mode, violation, details);
         }
     }
 
@@ -1222,7 +1228,13 @@ public class HttpConnection extends AbstractConnection implements Runnable, Writ
                 if (_uri.isAbsolute())
                 {
                     if (!_hostField.getValue().equals(_uri.getAuthority()))
-                        throw new BadMessageException("Authority!=Host");
+                    {
+                        HttpCompliance httpCompliance = getHttpConfiguration().getHttpCompliance();
+                        if (httpCompliance.allows(MISMATCHED_AUTHORITY))
+                            onComplianceViolation(httpCompliance, MISMATCHED_AUTHORITY, _uri.asString());
+                        else
+                            throw new BadMessageException("Authority!=Host");
+                    }
                 }
                 else
                 {
diff --git a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/ForwardedRequestCustomizerTest.java b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/ForwardedRequestCustomizerTest.java
index 7a5b24606a4..d8ddbd24a6d 100644
--- a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/ForwardedRequestCustomizerTest.java
+++ b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/ForwardedRequestCustomizerTest.java
@@ -20,6 +20,7 @@ import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.stream.Stream;
 
+import org.eclipse.jetty.http.HttpCompliance;
 import org.eclipse.jetty.http.HttpTester;
 import org.eclipse.jetty.util.Callback;
 import org.junit.jupiter.api.AfterEach;
@@ -64,7 +65,10 @@ public class ForwardedRequestCustomizerTest
 
         // Default behavior Connector
         HttpConnectionFactory http = new HttpConnectionFactory();
+        HttpCompliance mismatchedAuthorityHttpCompliance = HttpCompliance.RFC7230.with("Mismatched_Authority", HttpCompliance.Violation.MISMATCHED_AUTHORITY);
+        http.getHttpConfiguration().setHttpCompliance(mismatchedAuthorityHttpCompliance);
         http.getHttpConfiguration().setSecurePort(443);
+
         customizer = new ForwardedRequestCustomizer();
         http.getHttpConfiguration().addCustomizer(customizer);
         connector = new LocalConnector(server, http);
@@ -73,6 +77,7 @@ public class ForwardedRequestCustomizerTest
         // Alternate behavior Connector
         HttpConnectionFactory httpAlt = new HttpConnectionFactory();
         httpAlt.getHttpConfiguration().setSecurePort(8443);
+        httpAlt.getHttpConfiguration().setHttpCompliance(mismatchedAuthorityHttpCompliance);
         customizerAlt = new ForwardedRequestCustomizer();
         httpAlt.getHttpConfiguration().addCustomizer(customizerAlt);
         connectorAlt = new LocalConnector(server, httpAlt);
@@ -93,6 +98,7 @@ public class ForwardedRequestCustomizerTest
 
         http.getHttpConfiguration().addCustomizer(customizerConfigured);
         connectorConfigured = new LocalConnector(server, http);
+        connectorConfigured.getConnectionFactory(HttpConnectionFactory.class).getHttpConfiguration().setHttpCompliance(mismatchedAuthorityHttpCompliance);
         server.addConnector(connectorConfigured);
 
         RequestHandler handler = new RequestHandler();
diff --git a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/PartialRFC2616Test.java b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/PartialRFC2616Test.java
index 5e1cb473a16..a296dd716e6 100644
--- a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/PartialRFC2616Test.java
+++ b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/PartialRFC2616Test.java
@@ -17,6 +17,7 @@ import java.util.Date;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 
+import org.eclipse.jetty.http.HttpCompliance;
 import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.HttpFields;
 import org.eclipse.jetty.http.HttpParser;
@@ -48,6 +49,7 @@ public class PartialRFC2616Test
     {
         server = new Server();
         connector = new LocalConnector(server);
+        connector.getConnectionFactory(HttpConfiguration.ConnectionFactory.class).getHttpConfiguration().setHttpCompliance(HttpCompliance.RFC2616);
         connector.setIdleTimeout(10000);
         server.addConnector(connector);
 
@@ -403,13 +405,20 @@ public class PartialRFC2616Test
 
     }
 
+    /**
+     * @throws Exception
+     * @see <a href="https://www.rfc-editor.org/rfc/rfc2616#section-5.2">RFC 2616 - Section 5.2 - The Resource Identified by a Request</a>
+     */
     @Test
     @Disabled // TODO
     public void test521() throws Exception
     {
         // Default Host
         int offset = 0;
-        String response = connector.getResponse("GET http://VirtualHost:8888/path/R1 HTTP/1.1\n" + "Host: wronghost\n" + "Connection: close\n" + "\n");
+        String response = connector.getResponse(
+            "GET http://VirtualHost:8888/path/R1 HTTP/1.1\n" +
+            "Host: wronghost\n" +
+            "Connection: close\n" + "\n");
         offset = checkContains(response, offset, "HTTP/1.1 200", "Virtual host") + 1;
         offset = checkContains(response, offset, "Virtual Dump", "Virtual host") + 1;
         offset = checkContains(response, offset, "pathInContext=/path/R1", "Virtual host") + 1;
diff --git a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/NcsaRequestLogTest.java b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/NcsaRequestLogTest.java
index c98b162aff6..c15f165703c 100644
--- a/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/NcsaRequestLogTest.java
+++ b/jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/handler/NcsaRequestLogTest.java
@@ -163,7 +163,7 @@ public class NcsaRequestLogTest
 
         _connector.getResponse(
             "GET http://hostname:8888/foo?name=value HTTP/1.1\n" +
-                "Host: servername\n" +
+                "Host: hostname:8888\n" +
                 "\n");
         String log = _entries.poll(5, TimeUnit.SECONDS);
         assertThat(log, containsString("GET http://hostname:8888/foo?name=value"));
diff --git a/jetty-ee10/jetty-ee10-tests/jetty-ee10-test-integration/src/test/resources/RFC2616Base.xml b/jetty-ee10/jetty-ee10-tests/jetty-ee10-test-integration/src/test/resources/RFC2616Base.xml
index 9f6af74dd8e..b80ae305b73 100644
--- a/jetty-ee10/jetty-ee10-tests/jetty-ee10-test-integration/src/test/resources/RFC2616Base.xml
+++ b/jetty-ee10/jetty-ee10-tests/jetty-ee10-test-integration/src/test/resources/RFC2616Base.xml
@@ -22,6 +22,12 @@
       <Set name="sendDateHeader">false</Set>
       <Set name="headerCacheSize">1024</Set>
 
+      <Set name="httpCompliance">
+        <Call class="org.eclipse.jetty.http.HttpCompliance" name="from">
+          <Arg>RFC2616</Arg>
+        </Call>
+      </Set>
+
       <!-- Uncomment to enable handling of X-Forwarded- style headers
       <Call name="addCustomizer">
         <Arg><New class="org.eclipse.jetty.server.ForwardedRequestCustomizer"/></Arg>
diff --git a/jetty-ee9/jetty-ee9-nested/src/main/java/org/eclipse/jetty/ee9/nested/Request.java b/jetty-ee9/jetty-ee9-nested/src/main/java/org/eclipse/jetty/ee9/nested/Request.java
index 95afc0d668c..dd91c87801f 100644
--- a/jetty-ee9/jetty-ee9-nested/src/main/java/org/eclipse/jetty/ee9/nested/Request.java
+++ b/jetty-ee9/jetty-ee9-nested/src/main/java/org/eclipse/jetty/ee9/nested/Request.java
@@ -322,7 +322,7 @@ public class Request implements HttpServletRequest
                     cookieValue = cookieFields.get("value");
                     cookieMaxAge = cookieFields.get("max-age") != null ? Long.parseLong(cookieFields.get("max-age")) : -1;
                 }
-                
+
                 if (cookieMaxAge > 0)
                     cookies.put(cookieName, cookieValue);
                 else
diff --git a/jetty-ee9/jetty-ee9-nested/src/test/java/org/eclipse/jetty/ee9/nested/RequestTest.java b/jetty-ee9/jetty-ee9-nested/src/test/java/org/eclipse/jetty/ee9/nested/RequestTest.java
index 0813a230917..37da7ec0c91 100644
--- a/jetty-ee9/jetty-ee9-nested/src/test/java/org/eclipse/jetty/ee9/nested/RequestTest.java
+++ b/jetty-ee9/jetty-ee9-nested/src/test/java/org/eclipse/jetty/ee9/nested/RequestTest.java
@@ -901,6 +901,19 @@ public class RequestTest
         i = 0;
         assertThat(response, containsString("400 Bad"));
 
+        results.clear();
+        response = _connector.getResponse(
+            "GET http://myhost:8888/ HTTP/1.1\n" +
+                "Host: myhost:8888\n" +
+                "Connection: close\n" +
+                "\n");
+        i = 0;
+        assertThat(response, containsString("200 OK"));
+        assertEquals("http://myhost:8888/", results.get(i++));
+        assertEquals("0.0.0.0", results.get(i++));
+        assertEquals("myhost", results.get(i++));
+        assertEquals("8888", results.get(i));
+
         results.clear();
         response = _connector.getResponse(
             "GET / HTTP/1.1\n" +