diff --git a/default.nginx.conf b/default.nginx.conf
index acfb268..86357e6 100644
--- a/default.nginx.conf
+++ b/default.nginx.conf
@@ -2,10 +2,14 @@ events {}
 
 stream {
     server {
+        set $nginx_proxy_source_port '';
+        set $nginx_proxy_source_address '';
+
         content_by_lua_block {
              ngx.var.nginx_proxy_source_port = os.getenv("$NGINX_PROXY_SOURCE_PORT");
              ngx.var.nginx_proxy_source_address = os.getenv("$NGINX_PROXY_SOURCE_ADDRESS");
         }
+
         listen $nginx_proxy_source_port;
         proxy_pass $nginx_proxy_source_address;
     }