diff --git a/usr.sbin/iovctl/iovctl.c b/usr.sbin/iovctl/iovctl.c
index e25320e9b932..0350c732f671 100644
--- a/usr.sbin/iovctl/iovctl.c
+++ b/usr.sbin/iovctl/iovctl.c
@@ -230,17 +230,21 @@ main(int argc, char **argv)
 		usage();
 	}
 
-	if (device == NULL && filename == NULL) {
+	if (device == NULL && filename == NULL  && action != CONFIG) {
 		warnx("Either the -d or -f flag must be specified");
 		usage();
 	}
 
 	switch (action) {
 	case CONFIG:
-		if (filename == NULL) {
+		if (device != NULL) {
 			warnx("-d flag cannot be used with the -C flag");
 			usage();
 		}
+		if (filename == NULL) {
+			warnx("The -f flag must be specified");
+			usage();
+		}
 		config_action(filename, dryrun);
 		break;
 	case DELETE: