diff --git a/npa/src/sm.c b/npa/src/sm.c
index e651306..e723ec4 100644
--- a/npa/src/sm.c
+++ b/npa/src/sm.c
@@ -18,7 +18,11 @@
  */
 #include "scutil.h"
 #include "sm.h"
+#ifdef _WIN32
+#include <winsock2.h>
+#else
 #include <arpa/inet.h>
+#endif
 #include <libopensc/asn1.h>
 #include <libopensc/log.h>
 #include <stdlib.h>