diff --git a/src/csharp/Grpc.Examples.MathServer/MathServer.cs b/src/csharp/Grpc.Examples.MathServer/MathServer.cs
index 884a84d0a6c..f7429fb43f8 100644
--- a/src/csharp/Grpc.Examples.MathServer/MathServer.cs
+++ b/src/csharp/Grpc.Examples.MathServer/MathServer.cs
@@ -46,7 +46,7 @@ namespace math
 
             Server server = new Server();
             server.AddServiceDefinition(MathGrpc.BindService(new MathServiceImpl()));
-            int port = server.AddListeningPort(host + ":0");
+            int port = server.AddListeningPort(host + ":23456");
             server.Start();
 
             Console.WriteLine("MathServer listening on port " + port);