diff --git a/tailcfg/tailcfg.go b/tailcfg/tailcfg.go
index dd7d13ec5..b0969b085 100644
--- a/tailcfg/tailcfg.go
+++ b/tailcfg/tailcfg.go
@@ -1195,7 +1195,7 @@ type PingRequest struct {
 type MapResponse struct {
 	// KeepAlive, if set, represents an empty message just to keep
 	// the connection alive. When true, all other fields except
-	// PingRequestURL are ignored.
+	// PingRequest are ignored.
 	KeepAlive bool `json:",omitempty"`
 
 	// PingRequest, if non-empty, is a request to the client to