diff --git a/src/croc/croc.go b/src/croc/croc.go
index 6037a1a7..d070b74b 100644
--- a/src/croc/croc.go
+++ b/src/croc/croc.go
@@ -251,7 +251,7 @@ func (c *Client) Send(options TransferOptions) (err error) {
 		go func() {
 			discoveries, err := peerdiscovery.Discover(peerdiscovery.Settings{
 				Limit:     1,
-				Payload:   []byte("9009"),
+				Payload:   []byte(c.Options.RelayPorts[0]),
 				Delay:     10 * time.Millisecond,
 				TimeLimit: 30 * time.Second,
 			})