diff --git a/src/proxy_v1.c b/src/proxy_v1.c
index 93c9c0b8..6546a806 100644
--- a/src/proxy_v1.c
+++ b/src/proxy_v1.c
@@ -1,5 +1,6 @@
 #ifdef WIN32
 #  include <winsock2.h>
+#  include <ws2tcpip.h>
 #else
 #  include <arpa/inet.h>
 #endif