diff --git a/config/c3d2.nix b/config/c3d2.nix
index 65e78cd2..355992db 100644
--- a/config/c3d2.nix
+++ b/config/c3d2.nix
@@ -1,10 +1,11 @@
 # This module sets configuration for all NixOS machines defined in this flake
 
-{ config, options, lib, pkgs, ... }:
+{ zentralwerk, config, options, lib, pkgs, ... }:
 
 let
-  # TODO: Is this stable? Is there a better place to specifiy this?
-  hqPrefix64 = "fd23:42:c3d2:523";
+  hqPrefix64 = builtins.head (
+    builtins.split "/" zentralwerk.lib.config.site.net.c3d2.subnets6.dn42
+  );
 
   # Generate a deterministic IPv6 address for a 64 bit prefix
   # and seed string. Prefix must not contain trailing ':'.