diff --git a/src/http/ngx_http.c b/src/http/ngx_http.c
index 99ccef934..534fabf1b 100644
--- a/src/http/ngx_http.c
+++ b/src/http/ngx_http.c
@@ -1352,6 +1352,10 @@ ngx_http_optimize_servers(ngx_conf_t *cf, ngx_http_core_main_conf_t *cmcf,
     ngx_http_conf_port_t  *port;
     ngx_http_conf_addr_t  *addr;
 
+    if (ports == NULL) {
+        return NGX_OK;
+    }
+
     port = ports->elts;
     for (p = 0; p < ports->nelts; p++) {