diff --git a/src/Exercise/TimeServer.php b/src/Exercise/TimeServer.php
index ae1dada..b5ec382 100644
--- a/src/Exercise/TimeServer.php
+++ b/src/Exercise/TimeServer.php
@@ -10,7 +10,6 @@
 use PhpSchool\PhpWorkshop\Exercise\ExerciseInterface;
 use PhpSchool\PhpWorkshop\Exercise\ExerciseType;
 use PhpSchool\PhpWorkshop\Exercise\Scenario\CliScenario;
-use PhpSchool\PhpWorkshop\ExerciseDispatcher;
 use PhpSchool\PhpWorkshop\Output\OutputInterface;
 use PhpSchool\PhpWorkshop\Result\ComparisonFailure;
 use PhpSchool\PhpWorkshop\Result\Failure;
@@ -31,43 +30,50 @@ public function getDescription(): string
 
     public function defineListeners(EventDispatcher $eventDispatcher): void
     {
-        $appendArgsListener = function (CliExecuteEvent $event) {
-            $event->appendArg('127.0.0.1');
-            $event->appendArg($this->getRandomPort());
-        };
-
-        $eventDispatcher->listen('cli.verify.reference-execute.pre', $appendArgsListener);
-        $eventDispatcher->listen('cli.verify.student-execute.pre', $appendArgsListener);
-        $eventDispatcher->listen('cli.run.student-execute.pre', $appendArgsListener);
-
-        $eventDispatcher->listen('cli.verify.reference.executing', function (CliExecuteEvent $event) {
-            $args = $event->getArgs()->getArrayCopy();
+        $referencePort = $this->getRandomPort();
+        $studentPort = $this->getRandomPort();
+
+        $eventDispatcher->listen('cli.verify.reference-execute.pre',
+            function (CliExecuteEvent $event) use ($referencePort) {
+                $event->appendArg('127.0.0.1');
+                $event->appendArg($referencePort);
+                $event->getScenario()->exposePort($referencePort);
+            }
+        );
+        $eventDispatcher->listen(
+            ['cli.verify.student-execute.pre', 'cli.run.student-execute.pre'],
+            function (CliExecuteEvent $event) use ($studentPort) {
+                $event->appendArg('127.0.0.1');
+                $event->appendArg($studentPort);
+                $event->getScenario()->exposePort($studentPort);
+            }
+        );
 
+        $eventDispatcher->listen('cli.verify.reference.executing', function (CliExecuteEvent $event) use ($referencePort) {
             //wait for server to boot
             usleep(100000);
 
             $socket = $this->createSocket();
-            socket_connect($socket, $args[0], (int) $args[1]);
+
+            $connectResult = @socket_connect($socket, '127.0.0.1', $referencePort);
             socket_read($socket, 2048, PHP_NORMAL_READ);
 
             //wait for shutdown
             usleep(100000);
         });
 
-        $eventDispatcher->insertVerifier('cli.verify.student.executing', function (CliExecuteEvent $event) {
-            $args = $event->getArgs()->getArrayCopy();
-
+        $eventDispatcher->insertVerifier('cli.verify.student.executing', function (CliExecuteEvent $event) use ($studentPort) {
             //wait for server to boot
             usleep(100000);
 
             $socket = $this->createSocket();
-            $connectResult = @socket_connect($socket, $args[0], (int) $args[1]);
+            $connectResult = @socket_connect($socket, '127.0.0.1', $studentPort);
 
             if (!$connectResult) {
                 return Failure::fromNameAndReason($this->getName(), sprintf(
                     "Client returns an error (number %d): Connection refused while trying to join tcp://127.0.0.1:%d.",
                     socket_last_error($socket),
-                    $args[1]
+                    $studentPort
                 ));
             }
 
@@ -86,16 +92,25 @@ public function defineListeners(EventDispatcher $eventDispatcher): void
             return new Success($this->getName());
         });
 
-        $eventDispatcher->listen('cli.run.student.executing', function (CliExecuteEvent $event) {
+        $eventDispatcher->listen('cli.run.student.executing', function (CliExecuteEvent $event) use ($studentPort) {
             /** @var OutputInterface $output */
             $output = $event->getParameter('output');
-            $args   = $event->getArgs()->getArrayCopy();
 
             //wait for server to boot
             usleep(100000);
 
             $socket = $this->createSocket();
-            socket_connect($socket, $args[0], (int) $args[1]);
+            try {
+                $connectResult = @socket_connect($socket, '127.0.0.1', $studentPort);
+            } catch (\ErrorException $e) {
+                $output->write('Cannot connect');
+                return;
+            }
+
+            if (false === $connectResult) {
+                $output->write('Cannot connect');
+                return;
+            }
             $out = (string) socket_read($socket, 2048, PHP_NORMAL_READ);
 
             //wait for shutdown
@@ -107,7 +122,7 @@ public function defineListeners(EventDispatcher $eventDispatcher): void
 
     private function getRandomPort(): string
     {
-        return (string) mt_rand(1025, 65535);
+        return mt_rand(8001, 10000);
     }
 
     public function getType(): ExerciseType
@@ -117,7 +132,8 @@ public function getType(): ExerciseType
 
     public function defineTestScenario(): CliScenario
     {
-        return (new CliScenario())->withExecution();
+        return (new CliScenario())
+            ->withExecution();
     }
 
     private function createSocket(): Socket