diff --git a/internal/nettest/rlimit.go b/internal/nettest/rlimit.go
new file mode 100644
index 0000000..bb34aec
--- /dev/null
+++ b/internal/nettest/rlimit.go
@@ -0,0 +1,11 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package nettest
+
+const defaultMaxOpenFiles = 256
+
+// MaxOpenFiles returns the maximum number of open files for the
+// caller's process.
+func MaxOpenFiles() int { return maxOpenFiles() }