diff --git a/mbus/mbus-tcp.c b/mbus/mbus-tcp.c
index c089bf5..d4498ee 100755
--- a/mbus/mbus-tcp.c
+++ b/mbus/mbus-tcp.c
@@ -17,6 +17,7 @@
 #include <windows.h>
 #include <stdlib.h>
 #include <io.h>
+#include <ws2tcpip.h>
 
 #include <BaseTsd.h>
 typedef SSIZE_T ssize_t;