diff --git a/cmd/quictpu/ping/ping.go b/cmd/quictpu/ping/ping.go
index 0ef664b..69b8921 100644
--- a/cmd/quictpu/ping/ping.go
+++ b/cmd/quictpu/ping/ping.go
@@ -37,7 +37,7 @@ func main() {
 
 	var (
 		qconf quic.Config
-		dbg   *os.File
+		dbg   io.Writer
 		err   error
 	)
 	if *flagDebug {