mathserver listens on fixed port
diff --git a/src/csharp/Grpc.Examples.MathServer/MathServer.cs b/src/csharp/Grpc.Examples.MathServer/MathServer.cs
index 884a84d..f7429fb 100644
--- a/src/csharp/Grpc.Examples.MathServer/MathServer.cs
+++ b/src/csharp/Grpc.Examples.MathServer/MathServer.cs
@@ -46,7 +46,7 @@
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);