diff --git a/src/core/ngx_connection.c b/src/core/ngx_connection.c
index 242d0b78ca..bf52c3f6f3 100644
--- a/src/core/ngx_connection.c
+++ b/src/core/ngx_connection.c
@@ -489,11 +489,14 @@ ngx_open_listening_sockets(ngx_cycle_t *cycle)
             }
 
 #if (NGX_HAVE_MPTCP)
-            s = ngx_socket(ls[i].sockaddr->sa_family, ls[i].type,
+            s = (ngx_socket_t) -1;
+            if (ls[i].protocol > 0)
+                s = ngx_socket(ls[i].sockaddr->sa_family, ls[i].type,
                             ls[i].protocol);
-#else
-            s = ngx_socket(ls[i].sockaddr->sa_family, ls[i].type, 0);
+            if (s == (ngx_socket_t) -1)
 #endif
+            s = ngx_socket(ls[i].sockaddr->sa_family, ls[i].type, 0);
+            
             if (s == (ngx_socket_t) -1) {
                 ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
                               ngx_socket_n " %V failed", &ls[i].addr_text);