diff --git a/pkgs/development/python-modules/pymilter/default.nix b/pkgs/development/python-modules/pymilter/default.nix
index 60f00f40464f..eaeb815b55b9 100644
--- a/pkgs/development/python-modules/pymilter/default.nix
+++ b/pkgs/development/python-modules/pymilter/default.nix
@@ -5,8 +5,6 @@
   libmilter,
   berkeleydb,
   py3dns,
-  iana-etc,
-  libredirect,
   pyasyncore,
   setuptools,
 }:
@@ -26,24 +24,26 @@ buildPythonPackage rec {
   build-system = [
     setuptools
   ];
+
   buildInputs = [ libmilter ];
-  nativeCheckInputs = [ pyasyncore ];
+
+  nativeCheckInputs = [
+    pyasyncore
+  ];
+
   dependencies = [
     berkeleydb
     py3dns
   ];
 
   preBuild = ''
-    sed -i 's/import thread/import _thread as thread/' Milter/greylist.py
+    substituteInPlace Milter/greylist.py \
+      --replace-fail "import thread" "import _thread as thread"
   '';
 
-  # requires /etc/resolv.conf
   # testpolicy: requires makemap (#100419)
   #   using exec -a makemap smtpctl results in "unknown group smtpq"
   preCheck = ''
-    echo "nameserver 127.0.0.1" > resolv.conf
-    export NIX_REDIRECTS=/etc/protocols=${iana-etc}/etc/protocols:/etc/resolv.conf=$(realpath resolv.conf)
-    export LD_PRELOAD=${libredirect}/lib/libredirect.so
     sed -i '/testpolicy/d' test.py
     rm testpolicy.py
   '';