diff --git a/src/user_engine/runtime.py b/src/user_engine/runtime.py
index 92b453d..acce4bd 100644
--- a/src/user_engine/runtime.py
+++ b/src/user_engine/runtime.py
@@ -48,7 +48,9 @@ def create_application() -> PortalApplication:
 
 def main() -> None:
     host = os.environ.get("USER_ENGINE_HOST", "0.0.0.0")
-    port = int(os.environ.get("USER_ENGINE_PORT", "8080"))
+    # ``USER_ENGINE_PORT`` is reserved by Kubernetes service-link injection
+    # (for example ``tcp://10.43.0.1:8080``), so use an unambiguous setting.
+    port = int(os.environ.get("USER_ENGINE_HTTP_PORT", "8080"))
     with make_server(host, port, create_application()) as server:
         server.serve_forever()