diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyWebServer.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyWebServer.java
index 1d6ba620d5..aebc93149d 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyWebServer.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyWebServer.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -207,18 +207,6 @@ public class JettyWebServer implements WebServer {
 		return ports.toString();
 	}
 
-	private Integer getLocalPort(Connector connector) {
-		try {
-			// Jetty 9 internals are different, but the method name is the same
-			return (Integer) ReflectionUtils
-					.invokeMethod(ReflectionUtils.findMethod(connector.getClass(), "getLocalPort"), connector);
-		}
-		catch (Exception ex) {
-			logger.info("could not determine port ( " + ex.getMessage() + ")");
-			return 0;
-		}
-	}
-
 	private String getProtocols(Connector connector) {
 		List<String> protocols = connector.getProtocols();
 		return " (" + StringUtils.collectionToDelimitedString(protocols, ", ") + ")";
@@ -276,8 +264,29 @@ public class JettyWebServer implements WebServer {
 	public int getPort() {
 		Connector[] connectors = this.server.getConnectors();
 		for (Connector connector : connectors) {
-			// Probably only one...
-			return getLocalPort(connector);
+			Integer localPort = getLocalPort(connector);
+			if (localPort != null && localPort > 0) {
+				return localPort;
+			}
+		}
+		return -1;
+	}
+
+	private Integer getLocalPort(Connector connector) {
+		try {
+			if (connector instanceof NetworkConnector) {
+				return ((NetworkConnector) connector).getLocalPort();
+			}
+		}
+		catch (Exception ex) {
+		}
+		try {
+			// Jetty 9 internals are different, but the method name is the same
+			return (Integer) ReflectionUtils
+					.invokeMethod(ReflectionUtils.findMethod(connector.getClass(), "getLocalPort"), connector);
+		}
+		catch (Exception ex) {
+			logger.info("could not determine port ( " + ex.getMessage() + ")");
 		}
 		return 0;
 	}
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/netty/NettyWebServer.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/netty/NettyWebServer.java
index e2daf9bde3..f3c5697e1b 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/netty/NettyWebServer.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/netty/NettyWebServer.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -217,7 +217,7 @@ public class NettyWebServer implements WebServer {
 				return -1;
 			}
 		}
-		return 0;
+		return -1;
 	}
 
 }
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatWebServer.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatWebServer.java
index 6f282bb15d..25c260c4f0 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatWebServer.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatWebServer.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -364,7 +364,7 @@ public class TomcatWebServer implements WebServer {
 		if (connector != null) {
 			return connector.getLocalPort();
 		}
-		return 0;
+		return -1;
 	}
 
 	private String getContextPath() {
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/undertow/UndertowWebServer.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/undertow/UndertowWebServer.java
index 5715f1ea3c..5278bf6920 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/undertow/UndertowWebServer.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/undertow/UndertowWebServer.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -295,7 +295,7 @@ public class UndertowWebServer implements WebServer {
 	public int getPort() {
 		List<Port> ports = getActualPorts();
 		if (ports.isEmpty()) {
-			return 0;
+			return -1;
 		}
 		return ports.get(0).getNumber();
 	}
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/reactive/server/AbstractReactiveWebServerFactoryTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/reactive/server/AbstractReactiveWebServerFactoryTests.java
index 5db51932a1..25d1bea19d 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/reactive/server/AbstractReactiveWebServerFactoryTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/reactive/server/AbstractReactiveWebServerFactoryTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -115,6 +115,16 @@ public abstract class AbstractReactiveWebServerFactoryTests {
 		assertThat(this.webServer.getPort()).isEqualTo(specificPort);
 	}
 
+	@Test
+	void portIsMinusOneWhenConnectionIsClosed() {
+		AbstractReactiveWebServerFactory factory = getFactory();
+		this.webServer = factory.getWebServer(new EchoHandler());
+		this.webServer.start();
+		assertThat(this.webServer.getPort()).isGreaterThan(0);
+		this.webServer.stop();
+		assertThat(this.webServer.getPort()).isEqualTo(-1);
+	}
+
 	@Test
 	void basicSslFromClassPath() {
 		testBasicSslWithKeyStore("classpath:test.jks", "password");
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/servlet/server/AbstractServletWebServerFactoryTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/servlet/server/AbstractServletWebServerFactoryTests.java
index 7e92f7f48f..3b6b073491 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/servlet/server/AbstractServletWebServerFactoryTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/servlet/server/AbstractServletWebServerFactoryTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -250,7 +250,7 @@ public abstract class AbstractServletWebServerFactoryTests {
 		factory.setPort(-1);
 		this.webServer = factory.getWebServer(exampleServletRegistration());
 		this.webServer.start();
-		assertThat(this.webServer.getPort()).isLessThan(0); // Jetty is -2
+		assertThat(this.webServer.getPort()).isEqualTo(-1);
 	}
 
 	@Test
@@ -300,6 +300,16 @@ public abstract class AbstractServletWebServerFactoryTests {
 		assertThat(servlet.getInitCount()).isEqualTo(1);
 	}
 
+	@Test
+	void portIsMinusOneWhenConnectionIsClosed() {
+		AbstractServletWebServerFactory factory = getFactory();
+		this.webServer = factory.getWebServer();
+		this.webServer.start();
+		assertThat(this.webServer.getPort()).isGreaterThan(0);
+		this.webServer.stop();
+		assertThat(this.webServer.getPort()).isEqualTo(-1);
+	}
+
 	@Test
 	void specificPort() throws Exception {
 		AbstractServletWebServerFactory factory = getFactory();