diff --git a/core/net/ip/tcpip.c b/core/net/ip/tcpip.c
index 1c75d1bc9..839330ab7 100644
--- a/core/net/ip/tcpip.c
+++ b/core/net/ip/tcpip.c
@@ -155,6 +155,7 @@ unsigned char tcpip_is_forwarding; /* Forwarding right now? */
 PROCESS(tcpip_process, "TCP/IP stack");
 
 /*---------------------------------------------------------------------------*/
+#if UIP_TCP || UIP_CONF_IP_FORWARD
 static void
 start_periodic_tcp_timer(void)
 {
@@ -162,6 +163,7 @@ start_periodic_tcp_timer(void)
     etimer_restart(&periodic);
   }
 }
+#endif /* UIP_TCP || UIP_CONF_IP_FORWARD */
 /*---------------------------------------------------------------------------*/
 static void
 check_for_tcp_syn(void)