diff --git a/clientconn.go b/clientconn.go
index 91e4b7da315a..3269de08a2d9 100644
--- a/clientconn.go
+++ b/clientconn.go
@@ -37,7 +37,8 @@ import (
 	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/resolver"
-	_ "google.golang.org/grpc/resolver/dns" // To register dns resolver.
+	_ "google.golang.org/grpc/resolver/dns"         // To register dns resolver.
+	_ "google.golang.org/grpc/resolver/passthrough" // To register passthrough resolver.
 	"google.golang.org/grpc/stats"
 	"google.golang.org/grpc/transport"
 )
diff --git a/resolver/passthrough/passthrough.go b/resolver/passthrough/passthrough.go
index 4d4420aa4168..b76010d74d14 100644
--- a/resolver/passthrough/passthrough.go
+++ b/resolver/passthrough/passthrough.go
@@ -17,8 +17,7 @@
  */
 
 // Package passthrough implements a pass-through resolver. It sends the target
-// name without scheme back to gRPC as resolved address. It's for gRPC internal
-// test only.
+// name without scheme back to gRPC as resolved address.
 package passthrough
 
 import "google.golang.org/grpc/resolver"
diff --git a/resolver/resolver.go b/resolver/resolver.go
index 6e822b56bef6..0dd887fa5436 100644
--- a/resolver/resolver.go
+++ b/resolver/resolver.go
@@ -24,7 +24,7 @@ var (
 	// m is a map from scheme to resolver builder.
 	m = make(map[string]Builder)
 	// defaultScheme is the default scheme to use.
-	defaultScheme = "dns"
+	defaultScheme = "passthrough"
 )
 
 // TODO(bar) install dns resolver in init(){}.