diff --git a/port/lwipopts.h b/port/lwipopts.h
index 7a40cd74..3c7e3b58 100644
--- a/port/lwipopts.h
+++ b/port/lwipopts.h
@@ -179,7 +179,7 @@
  * MEMP_NUM_SYS_TIMEOUT: the number of simulateously active timeouts.
  * (requires NO_SYS==0)
  */
-#define MEMP_NUM_SYS_TIMEOUT            LWIP_NUM_SYS_TIMEOUT_INTERNAL + 4
+#define MEMP_NUM_SYS_TIMEOUT            LWIP_NUM_SYS_TIMEOUT_INTERNAL + 10
 
 /**
  * MEMP_NUM_NETBUF: the number of struct netbufs.