diff --git a/ports/win32/test.c b/ports/win32/test.c
index 225e2b0..abc1939 100644
--- a/ports/win32/test.c
+++ b/ports/win32/test.c
@@ -113,7 +113,7 @@ struct netif loop_netif;
 #endif /* LWIP_HAVE_LOOPIF */
 #if PPP_SUPPORT
 /* THE PPP descriptor */
-int ppp_desc;
+int ppp_desc = -1;
 #endif /* PPP_SUPPORT */