diff --git a/ip2net/ip2net.c b/ip2net/ip2net.c
index d8d33ac..83bddc1 100644
--- a/ip2net/ip2net.c
+++ b/ip2net/ip2net.c
@@ -11,8 +11,10 @@
 #include <stdint.h>
 #include <string.h>
 #ifdef _WIN32
+#undef _WIN32_WINNT
+#define _WIN32_WINNT 0x600
 #include <winsock2.h>
-#include <Ws2ipdef.h>
+#include <ws2ipdef.h>
 #include <ws2tcpip.h>
 #else
 #include <arpa/inet.h>