diff --git a/vscode-extensions/vscode-manifest-yaml/src/main/java/org/springframework/ide/vscode/manifest/yaml/RouteValueParser.java b/vscode-extensions/vscode-manifest-yaml/src/main/java/org/springframework/ide/vscode/manifest/yaml/RouteValueParser.java
index 998f44208..67e329516 100644
--- a/vscode-extensions/vscode-manifest-yaml/src/main/java/org/springframework/ide/vscode/manifest/yaml/RouteValueParser.java
+++ b/vscode-extensions/vscode-manifest-yaml/src/main/java/org/springframework/ide/vscode/manifest/yaml/RouteValueParser.java
@@ -6,15 +6,18 @@ import java.util.concurrent.Callable;
 import java.util.regex.Matcher;
 
 import org.springframework.ide.vscode.commons.cloudfoundry.client.CFRoute;
+import org.springframework.ide.vscode.commons.cloudfoundry.client.cftarget.ConnectionException;
+import org.springframework.ide.vscode.commons.cloudfoundry.client.cftarget.NoTargetsException;
 import org.springframework.ide.vscode.commons.languageserver.reconcile.ReconcileException;
 import org.springframework.ide.vscode.commons.util.RegexpParser;
 import org.springframework.ide.vscode.commons.util.ValueParseException;
 
 public class RouteValueParser extends RegexpParser {
 	
-	private static final String ROUTE_REGEX = "^([\\da-z\\.-]+)(:\\d{1,4})?((\\/[\\dA-Za-z\\.-]+)*\\/?)?$";
+	private static final String ROUTE_REGEX = "^([\\da-z\\.-]+)(:\\d{1,5})?((\\/[\\dA-Za-z\\.-]+)*\\/?)?$";
 	private static final String ROUTE_TYPE_NAME = "Route";
 	private static final String ROUTE_DESCRIPTION = "HTTP or TCP application root route";
+	private static final int MAX_PORT_NUMBER = 65535;
 	
 	private Callable<Collection<String>> domains;
 
@@ -22,12 +25,24 @@ public class RouteValueParser extends RegexpParser {
 		super(ROUTE_REGEX, ROUTE_TYPE_NAME, ROUTE_DESCRIPTION);
 		this.domains = domains;
 	}
-
-	@Override
-	public Object parse(String str) throws Exception {
-		Matcher matcher = (Matcher) super.parse(str);
-		if (matcher != null) {
-			Collection<String> cloudDomains = domains == null ? Collections.emptyList() : domains.call();
+	
+	private Matcher staticValidation(String str) throws Exception {
+		return (Matcher) super.parse(str);
+	}
+	
+	private Object dynamicValidation(String str, Matcher matcher) throws Exception {
+		try {
+			Collection<String> cloudDomains = Collections.emptyList();
+			try {
+				cloudDomains = domains == null ? Collections.emptyList() : domains.call();
+			} catch (ValueParseException e) {
+				/*
+				 * If domains hint provider throws exception it is
+				 * ValueParserException not NoTargetsException. This means no
+				 * communication with CF -> abort dyncamic validation
+				 */
+				return matcher;
+			}
 			// Ensure cloud domains is empty list instead of null
 			if (cloudDomains == null) {
 				cloudDomains = Collections.emptyList();
@@ -40,11 +55,28 @@ public class RouteValueParser extends RegexpParser {
 				throw new ValueParseException(
 						"Unable to determine type of route. HTTP port may have a path but no port. TCP route may have port but no path.");
 			}
+			if (route.getPort() > MAX_PORT_NUMBER) {
+				String portAndColumn = matcher.group(2);
+				int start = str.indexOf(portAndColumn) + 1;
+				int end = start + portAndColumn.length() - 1;
+				throw new ValueParseException("Invalid port number. Port range must be between 1 and " + MAX_PORT_NUMBER, start, end);
+			}
 			if (!cloudDomains.contains(route.getDomain())) {
 				String hostDomain = matcher.group(1);
 				throw new ReconcileException("Unknown domain", ManifestYamlSchemaProblemsTypes.UNKNOWN_DOMAIN_PROBLEM, hostDomain.lastIndexOf(route.getDomain()), hostDomain.length());
 			}
 			return route;
+		} catch (ConnectionException | NoTargetsException e) {
+			// No connection to CF? Abort dynamic validation
+			return matcher;
+		}
+	}
+	
+	@Override
+	public Object parse(String str) throws Exception {
+		Matcher matcher = staticValidation(str);
+		if (matcher != null) {
+			return dynamicValidation(str, matcher);
 		}
 		return null;
 	}
diff --git a/vscode-extensions/vscode-manifest-yaml/src/test/java/org/springframework/ide/vscode/manifest/yaml/ManifestYamlEditorTest.java b/vscode-extensions/vscode-manifest-yaml/src/test/java/org/springframework/ide/vscode/manifest/yaml/ManifestYamlEditorTest.java
index 4e6fe6b15..573d82b8f 100644
--- a/vscode-extensions/vscode-manifest-yaml/src/test/java/org/springframework/ide/vscode/manifest/yaml/ManifestYamlEditorTest.java
+++ b/vscode-extensions/vscode-manifest-yaml/src/test/java/org/springframework/ide/vscode/manifest/yaml/ManifestYamlEditorTest.java
@@ -1021,9 +1021,7 @@ public class ManifestYamlEditorTest {
 				"  routes:\n" +
 				"  - route: http://springsource.org\n");
 		editor.assertProblems("http://springsource.org|is not a valid 'Route'");
-
 		Diagnostic problem = editor.assertProblem("http://springsource.org");
-
 		assertEquals(DiagnosticSeverity.Error, problem.getSeverity());
 		
 		editor = harness.newEditor(
@@ -1032,9 +1030,7 @@ public class ManifestYamlEditorTest {
 				"  routes:\n" +
 				"  - route: spring source.org\n");
 		editor.assertProblems("spring source.org|is not a valid 'Route'");
-
 		problem = editor.assertProblem("spring source.org");
-
 		assertEquals(DiagnosticSeverity.Error, problem.getSeverity());
 
 		editor = harness.newEditor(
@@ -1043,9 +1039,7 @@ public class ManifestYamlEditorTest {
 				"  routes:\n" +
 				"  - route: springsource.org:kuku\n");
 		editor.assertProblems("springsource.org:kuku|is not a valid 'Route'");
-
 		problem = editor.assertProblem("springsource.org:kuku");
-
 		assertEquals(DiagnosticSeverity.Error, problem.getSeverity());
 
 	
@@ -1055,9 +1049,16 @@ public class ManifestYamlEditorTest {
 				"  routes:\n" +
 				"  - route: springsource.org/kuku?p=23\n");
 		editor.assertProblems("springsource.org/kuku?p=23|is not a valid 'Route'");
-
 		problem = editor.assertProblem("springsource.org/kuku?p=23");
+		assertEquals(DiagnosticSeverity.Error, problem.getSeverity());
 
+		editor = harness.newEditor(
+				"applications:\n" +
+				"- name: foo\n" +
+				"  routes:\n" +
+				"  - route: springsource.org:645788\n");
+		editor.assertProblems("springsource.org:645788|is not a valid 'Route'");
+		problem = editor.assertProblem("springsource.org:645788");
 		assertEquals(DiagnosticSeverity.Error, problem.getSeverity());
 	}
 
@@ -1069,9 +1070,16 @@ public class ManifestYamlEditorTest {
 				"  routes:\n" +
 				"  - route: springsource.org:8765/path\n");
 		editor.assertProblems("springsource.org:8765/path|Unable to determine type of route");
-
 		Diagnostic problem = editor.assertProblem("springsource.org:8765/path");
-
+		assertEquals(DiagnosticSeverity.Error, problem.getSeverity());
+		
+		editor = harness.newEditor(
+				"applications:\n" +
+				"- name: foo\n" +
+				"  routes:\n" +
+				"  - route: host.springsource.org:66000\n");
+		editor.assertProblems("66000|Invalid port");
+		problem = editor.assertProblem("66000");
 		assertEquals(DiagnosticSeverity.Error, problem.getSeverity());
 		
 		editor = harness.newEditor(
@@ -1080,9 +1088,7 @@ public class ManifestYamlEditorTest {
 				"  routes:\n" +
 				"  - route: host.springsource.org\n");
 		editor.assertProblems("springsource.org|Unknown domain");
-
 		problem = editor.assertProblem("springsource.org");
-
 		assertEquals(DiagnosticSeverity.Warning, problem.getSeverity());
 	}