diff --git a/src/croc/croc.go b/src/croc/croc.go
index fac97cb6..ca1ade5e 100644
--- a/src/croc/croc.go
+++ b/src/croc/croc.go
@@ -716,7 +716,7 @@ func (c *Client) processMessageSalt(m message.Message) (done bool, err error) {
 }
 
 func (c *Client) processExternalIP(m message.Message) (done bool, err error) {
-	log.Debug("received external IP: %+v", m)
+	log.Debugf("received external IP: %+v", m)
 	if !c.Options.IsSender {
 		err = message.Send(c.conn[0], c.Key, message.Message{
 			Type:    "externalip",