diff --git a/Makefile b/Makefile
index c2ea18b..0ab587a 100644
--- a/Makefile
+++ b/Makefile
@@ -16,7 +16,8 @@ check-clean:
 		sed -n '/.*\.zone/{p;q1}'
 
 upload:
-	printf 'put %s\n' *.zone *.sig | sftp ns0.it-syndikat.org:zones/
+	printf 'put %s\n' *.zone *.sig | \
+		sftp $(SFTP_FLAGS) zones@ns0.it-syndikat.org:zones/
 
 clean:
 	rm -f *.sig