diff --git a/libports/include/lwip/lwipopts.h b/libports/include/lwip/lwipopts.h
index 6ef45266af..c710c70503 100644
--- a/libports/include/lwip/lwipopts.h
+++ b/libports/include/lwip/lwipopts.h
@@ -51,7 +51,7 @@
 
 #define TCP_MSS                  1460
 #define TCP_WND                     (32 * TCP_MSS)
-#define TCP_SND_BUF                 (128 * TCP_MSS)
+#define TCP_SND_BUF                 (128 * TCP_MSS > 65535 ? 65535 : 128 * TCP_MSS)
 #define TCP_SND_QUEUELEN            ((32 * (TCP_SND_BUF) + (TCP_MSS - 1))/(TCP_MSS))
 
 #define RECV_BUFSIZE_DEFAULT        2147483647 /* this is actually INT_MAX, default value */