diff --git a/src/cmsg.h b/src/cmsg.h
index 2f3e193..aa8812a 100644
--- a/src/cmsg.h
+++ b/src/cmsg.h
@@ -3,7 +3,7 @@
 
 #include <sys/uio.h>
 
-#define DATA_LEN_MAX 496 /* 512 - 16 bytes of header */
+#define DATA_LEN_MAX 1476 /* 1500 - (16 bytes of cmsg header + 8 bytes of udp) */
 #define DATA_ARGS_MAX 6  /* number of args in data */
 #define F2B_PROTO_VER 1