diff --git a/connect.c b/connect.c
index 722dc3f..5330d9c 100644
--- a/connect.c
+++ b/connect.c
@@ -730,7 +730,7 @@ struct child_process *git_connect(int fd[2], const char *url,
 		 * Note: Do not add any other headers here!  Doing so
 		 * will cause older git-daemon servers to crash.
 		 */
-		packet_write(fd[1],
+		packet_write_fmt(fd[1],
 			     "%s %s%chost=%s%c",
 			     prog, path, 0,
 			     target_host, 0);