diff --git a/common.h b/common.h
index a589e2b..b01b3a1 100644
--- a/common.h
+++ b/common.h
@@ -57,6 +57,7 @@
 
 #if defined(__MINGW32__)
 #include <winsock2.h>
+#include <ws2ipdef.h>
 typedef unsigned char u_int8_t;
 typedef unsigned short u_int16_t;
 typedef unsigned int u_int32_t;