diff --git a/proxy/core/listener/pool.py b/proxy/core/listener/pool.py
index f9befa9c17..b0945bfd10 100644
--- a/proxy/core/listener/pool.py
+++ b/proxy/core/listener/pool.py
@@ -39,9 +39,9 @@ def setup(self) -> None:
         if self.flags.unix_socket_path:
             self.add(UnixSocketListener)
         hostnames = {self.flags.hostname, *self.flags.hostnames}
-        ports = set(self.flags.ports)
+        ports = list(self.flags.ports)
         if not self.flags.unix_socket_path:
-            ports.add(self.flags.port)
+            ports.append(self.flags.port)
         for hostname, port in itertools.product(hostnames, ports):
             self.add(TcpSocketListener, hostname=hostname, port=port)