diff --git a/pkgs/development/haskell-modules/generic-builder.nix b/pkgs/development/haskell-modules/generic-builder.nix
index a0990a1972a3..f795deebddf4 100644
--- a/pkgs/development/haskell-modules/generic-builder.nix
+++ b/pkgs/development/haskell-modules/generic-builder.nix
@@ -262,6 +262,8 @@ in
   __onlyPropagateKnownPkgConfigModules ? false,
   enableExternalInterpreter ?
     isCross && crossSupport.canProxyTH && crossSupport.needsExternalInterpreterSetup,
+  # iserv-proxy needs local network access
+  __darwinAllowLocalNetworking ? stdenv.hostPlatform.isDarwin && enableExternalInterpreter,
 }@args:
 
 assert editedCabalFile != null -> revision != null;
@@ -1154,5 +1156,8 @@ lib.fix (
     // optionalAttrs (disallowedRequisites != [ ] || disallowGhcReference) {
       disallowedRequisites = disallowedRequisites ++ (if disallowGhcReference then [ ghc ] else [ ]);
     }
+    // optionalAttrs (__darwinAllowLocalNetworking || args ? __darwinLocalNetworking) {
+      __darwinAllowLocalNetworking = true;
+    }
   )
 )