diff --git a/test/templates/util/aspnet.ts b/test/templates/util/aspnet.ts
index 11d75ae..d320fc2 100644
--- a/test/templates/util/aspnet.ts
+++ b/test/templates/util/aspnet.ts
@@ -5,6 +5,7 @@ import { waitUntilPortState } from './ports';
 const treeKill = require('tree-kill');
 const crossSpawn: typeof childProcess.spawn = require('cross-spawn');
 const defaultPort = 5000;
+const defaultInterface = 'localhost';
 
 export const defaultUrl = `http://localhost:${ defaultPort }`;
 
@@ -99,7 +100,7 @@ export class AspNetProcess {
                     // any outstanding requests. We have to wait for it really to be gone before continuing, otherwise
                     // the next test might be unable to start because of the port still being in use.
                     console.log(`Waiting until port ${ defaultPort } is closed...`);
-                    waitUntilPortState(defaultPort, /* isOpen */ true, /* timeoutMs */ 15000, err => {
+                    waitUntilPortState(defaultPort, defaultInterface, /* isListening */ false, /* timeoutMs */ 15000, err => {
                         if (err) {
                             callback(err);
                         } else {
diff --git a/test/templates/util/ports.ts b/test/templates/util/ports.ts
index 5a124d6..197ebab 100644
--- a/test/templates/util/ports.ts
+++ b/test/templates/util/ports.ts
@@ -1,20 +1,21 @@
 import * as portastic from 'portastic';
 const pollInterval = 500;
 
-export function waitUntilPortState(port: number, isOpen: boolean, timeoutMs: number, callback: (err: any) => void) {
+export function waitUntilPortState(port: number, iface: string, isListening: boolean, timeoutMs: number, callback: (err: any) => void) {
     if (!(timeoutMs > 0)) {
-        throw new Error(`Timed out after ${ timeoutMs }ms waiting for port ${ port } to become ${ isOpen ? 'free' : 'in use' }`);
+        throw new Error(`Timed out waiting for port ${ port } to become ${ isListening ? 'in use' : 'free' }`);
     }
 
-    portastic.test(port).then(
-        actualIsOpenState => {
-            if (actualIsOpenState === isOpen) {
+    portastic.test(port, iface).then(
+        actuallyIsAvailable => {
+            const actuallyIsListening = !actuallyIsAvailable;
+            if (actuallyIsListening === isListening) {
                 // Desired state is reached
                 callback(null);
             } else {
                 // Wait longer
                 setTimeout(() => {
-                    waitUntilPortState(port, isOpen, timeoutMs - pollInterval, callback);
+                    waitUntilPortState(port, iface, isListening, timeoutMs - pollInterval, callback);
                 }, pollInterval);
             }
         },