diff --git a/libc/include/arpa/nameser.h b/libc/include/arpa/nameser.h
index ffb5250..e0b5c45 100644
--- a/libc/include/arpa/nameser.h
+++ b/libc/include/arpa/nameser.h
@@ -474,6 +474,7 @@
  */
 #define NS_OPT_DNSSEC_OK	0x8000U
 #define NS_OPT_NSID             3
+#define NS_OPT_PADDING          12
 
 /*
  * Inline versions of get/put short/long.  Pointer is advanced.