diff --git a/source3/rpc_client/rpc_transport.h b/source3/rpc_client/rpc_transport.h
index ad2210646fa..1c774583bdc 100644
--- a/source3/rpc_client/rpc_transport.h
+++ b/source3/rpc_client/rpc_transport.h
@@ -64,7 +64,7 @@ struct rpc_cli_transport {
 	 */
 	struct tevent_req *(*trans_send)(TALLOC_CTX *mem_ctx,
 					 struct tevent_context *ev,
-					 uint8_t *data, size_t data_len,
+					 const uint8_t *data, size_t data_len,
 					 uint32_t max_rdata_len,
 					 void *priv);
 	/**
diff --git a/source3/rpc_client/rpc_transport_tstream.c b/source3/rpc_client/rpc_transport_tstream.c
index dd0de081d1b..3d47d60402f 100644
--- a/source3/rpc_client/rpc_transport_tstream.c
+++ b/source3/rpc_client/rpc_transport_tstream.c
@@ -356,7 +356,7 @@ static int rpc_tstream_trans_next_vector(struct tstream_context *stream,
 
 static struct tevent_req *rpc_tstream_trans_send(TALLOC_CTX *mem_ctx,
 						 struct tevent_context *ev,
-						 uint8_t *data, size_t data_len,
+						 const uint8_t *data, size_t data_len,
 						 uint32_t max_rdata_len,
 						 void *priv)
 {