diff --git a/config.c b/config.c
index 7bb3b05..80fa255 100644
--- a/config.c
+++ b/config.c
@@ -607,6 +607,8 @@ struct interface *config_create_interface(char *name, struct config *cfg)
 	strncpy(iface->name, name, MAX_IFNAME_SIZE);
 	sk_get_ts_info(iface->name, &iface->ts_info);
 	STAILQ_INSERT_TAIL(&cfg->interfaces, iface, list);
+	cfg->n_interfaces++;
+
 	return iface;
 }
 
diff --git a/config.h b/config.h
index ad057e9..b02bde6 100644
--- a/config.h
+++ b/config.h
@@ -41,6 +41,7 @@ struct interface {
 struct config {
 	/* configured interfaces */
 	STAILQ_HEAD(interfaces_head, interface) interfaces;
+	int n_interfaces;
 
 	/* hash of all non-legacy items */
 	struct hash *htab;