diff --git a/pkgs/development/python-modules/portend/default.nix b/pkgs/development/python-modules/portend/default.nix
index 5da7a7941c0f..7aa66c2a3093 100644
--- a/pkgs/development/python-modules/portend/default.nix
+++ b/pkgs/development/python-modules/portend/default.nix
@@ -24,6 +24,9 @@ buildPythonPackage rec {
     py.test --deselect=test_portend.py::TestChecker::test_check_port_listening
   '';
 
+  # Some of the tests use localhost networking.
+  __darwinAllowLocalNetworking = true;
+
   meta = with stdenv.lib; {
     description = "Monitor TCP ports for bound or unbound states";
     homepage = https://github.com/jaraco/portend;