diff --git a/ares/ares_rules.h b/ares/ares_rules.h
index 95751b00fb9644c4dd1bd37fb0539c75d99c00ef..f67effebcd3f08c930b40660f021cfb1530c06f8 100644
--- a/ares/ares_rules.h
+++ b/ares/ares_rules.h
@@ -136,6 +136,7 @@ typedef char
  * Get rid of macros not intended to exist beyond this point.
  */
 
+#undef CARES_PULL_WS2TCPIP_H
 #undef CARES_PULL_SYS_TYPES_H
 #undef CARES_PULL_SYS_SOCKET_H