diff --git a/pkgs/development/python-modules/Logbook/default.nix b/pkgs/development/python-modules/Logbook/default.nix
index 866c0410929..503fefc0013 100644
--- a/pkgs/development/python-modules/Logbook/default.nix
+++ b/pkgs/development/python-modules/Logbook/default.nix
@@ -18,6 +18,9 @@ buildPythonPackage rec {
     py.test tests
   '';
 
+  # Some of the tests use localhost networking.
+  __darwinAllowLocalNetworking = true;
+
   meta = {
     homepage = https://pythonhosted.org/Logbook/;
     description = "A logging replacement for Python";
diff --git a/pkgs/development/python-modules/ipykernel/default.nix b/pkgs/development/python-modules/ipykernel/default.nix
index 5203047b77f..4bdd9011d1e 100644
--- a/pkgs/development/python-modules/ipykernel/default.nix
+++ b/pkgs/development/python-modules/ipykernel/default.nix
@@ -37,6 +37,9 @@ buildPythonPackage rec {
     HOME=$(mktemp -d) pytest ipykernel -k "not (test_sys_path or test_sys_path_profile_dir or test_complete)"
   '';
 
+  # Some of the tests use localhost networking.
+  __darwinAllowLocalNetworking = true;
+
   meta = {
     description = "IPython Kernel for Jupyter";
     homepage = http://ipython.org/;
diff --git a/pkgs/development/python-modules/nbconvert/default.nix b/pkgs/development/python-modules/nbconvert/default.nix
index 69828b2b18f..2f0090b5967 100644
--- a/pkgs/development/python-modules/nbconvert/default.nix
+++ b/pkgs/development/python-modules/nbconvert/default.nix
@@ -44,6 +44,9 @@ buildPythonPackage rec {
     HOME=$(mktemp -d) py.test -v --ignore="nbconvert/preprocessors/tests/test_execute.py"
   '';
 
+  # Some of the tests use localhost networking.
+  __darwinAllowLocalNetworking = true;
+
   meta = {
     description = "Converting Jupyter Notebooks";
     homepage = https://jupyter.org/;
diff --git a/pkgs/development/python-modules/nbformat/default.nix b/pkgs/development/python-modules/nbformat/default.nix
index 8b16ffb7e32..fbc71202d28 100644
--- a/pkgs/development/python-modules/nbformat/default.nix
+++ b/pkgs/development/python-modules/nbformat/default.nix
@@ -29,6 +29,9 @@ buildPythonPackage rec {
     export HOME=tmp
   '';
 
+  # Some of the tests use localhost networking.
+  __darwinAllowLocalNetworking = true;
+
   meta = {
     description = "The Jupyter Notebook format";
     homepage = https://jupyter.org/;
diff --git a/pkgs/development/python-modules/nbval/default.nix b/pkgs/development/python-modules/nbval/default.nix
index 60aa4806e2f..860142f1e94 100644
--- a/pkgs/development/python-modules/nbval/default.nix
+++ b/pkgs/development/python-modules/nbval/default.nix
@@ -45,6 +45,9 @@ buildPythonPackage rec {
     pytest tests --ignore tests/test_timeouts.py
   '';
 
+  # Some of the tests use localhost networking.
+  __darwinAllowLocalNetworking = true;
+
   meta = with lib; {
     description = "A py.test plugin to validate Jupyter notebooks";
     homepage = https://github.com/computationalmodelling/nbval;
diff --git a/pkgs/development/python-modules/notebook/default.nix b/pkgs/development/python-modules/notebook/default.nix
index 431d4bb4d56..d081a5a92fb 100644
--- a/pkgs/development/python-modules/notebook/default.nix
+++ b/pkgs/development/python-modules/notebook/default.nix
@@ -64,6 +64,9 @@ buildPythonPackage rec {
     else ""}
   '';
 
+  # Some of the tests use localhost networking.
+  __darwinAllowLocalNetworking = true;
+
   meta = {
     description = "The Jupyter HTML notebook is a web-based notebook environment for interactive computing";
     homepage = https://jupyter.org/;
diff --git a/pkgs/development/python-modules/pyzmq/default.nix b/pkgs/development/python-modules/pyzmq/default.nix
index dcab96d12a6..40273cce888 100644
--- a/pkgs/development/python-modules/pyzmq/default.nix
+++ b/pkgs/development/python-modules/pyzmq/default.nix
@@ -32,4 +32,7 @@ buildPythonPackage rec {
       and not test_on_recv_wake \
       and not test_monitor"
   '';
+
+  # Some of the tests use localhost networking.
+  __darwinAllowLocalNetworking = true;
 }