diff --git a/lib/isc/netscope.c b/lib/isc/netscope.c
index bca2d13801..68a0a8dc14 100644
--- a/lib/isc/netscope.c
+++ b/lib/isc/netscope.c
@@ -18,6 +18,7 @@
 #include <isc/netscope.h>
 #include <isc/result.h>
 #include <isc/string.h>
+#include <isc/util.h>
 
 isc_result_t
 isc_netscope_pton(int af, char *scopename, void *addr, uint32_t *zoneid) {
@@ -26,9 +27,13 @@ isc_netscope_pton(int af, char *scopename, void *addr, uint32_t *zoneid) {
 	unsigned int ifid;
 	struct in6_addr *in6;
 #endif /* ifdef HAVE_IF_NAMETOINDEX */
-	uint32_t zone;
+	uint32_t zone = 0;
 	uint64_t llz;
 
+#ifndef HAVE_IF_NAMETOINDEX
+	UNUSED(addr);
+#endif
+
 	/* at this moment, we only support AF_INET6 */
 	if (af != AF_INET6) {
 		return (ISC_R_FAILURE);