diff --git a/test/fixtures/clustered-server/app.js b/test/fixtures/clustered-server/app.js
index f89d70ee8f8ca6..cae204c25bd043 100644
--- a/test/fixtures/clustered-server/app.js
+++ b/test/fixtures/clustered-server/app.js
@@ -31,5 +31,5 @@ if (cluster.isMaster) {
   }
 } else {
   var server = http.createServer(handleRequest);
-  server.listen(common.PORT+1000);
+  server.listen(common.PORT);
 }
diff --git a/test/parallel/test-debug-port-cluster.js b/test/parallel/test-debug-port-cluster.js
index ba87a1ea3bff42..cc564b3ac1522c 100644
--- a/test/parallel/test-debug-port-cluster.js
+++ b/test/parallel/test-debug-port-cluster.js
@@ -3,7 +3,7 @@ const common = require('../common');
 const assert = require('assert');
 const spawn = require('child_process').spawn;
 
-const PORT_MIN = common.PORT;
+const PORT_MIN = common.PORT + 1;  // The fixture uses common.PORT.
 const PORT_MAX = PORT_MIN + 2;
 
 const args = [
diff --git a/test/parallel/test-debug-signal-cluster.js b/test/parallel/test-debug-signal-cluster.js
index 7a950458b87271..e51cd9a50ab29f 100644
--- a/test/parallel/test-debug-signal-cluster.js
+++ b/test/parallel/test-debug-signal-cluster.js
@@ -3,7 +3,7 @@ var common = require('../common');
 var assert = require('assert');
 var spawn = require('child_process').spawn;
 
-var port = common.PORT + 42;
+var port = common.PORT + 1;  // The fixture uses common.PORT.
 var args = ['--debug-port=' + port,
             common.fixturesDir + '/clustered-server/app.js'];
 var options = { stdio: ['inherit', 'inherit', 'pipe', 'ipc'] };