diff --git a/FGRoute/Classes/IpHelper.h b/FGRoute/Classes/IpHelper.h
index 71117db..79a55e2 100644
--- a/FGRoute/Classes/IpHelper.h
+++ b/FGRoute/Classes/IpHelper.h
@@ -10,6 +10,7 @@
 #define IpHelper_h
 
 #include <stdio.h>
+#include <sys/_types/_in_addr_t.h>
 
 int getdefaultgateway(in_addr_t * addr);