diff --git a/flake.lock b/flake.lock
index 54094ed2..903525e7 100644
--- a/flake.lock
+++ b/flake.lock
@@ -23,10 +23,7 @@
     },
     "fenix_2": {
       "inputs": {
-        "nixpkgs": [
-          "heliwatch",
-          "nixpkgs"
-        ],
+        "nixpkgs": "nixpkgs",
         "rust-analyzer-src": "rust-analyzer-src_2"
       },
       "locked": {
@@ -68,10 +65,7 @@
     },
     "naersk": {
       "inputs": {
-        "nixpkgs": [
-          "heliwatch",
-          "nixpkgs"
-        ]
+        "nixpkgs": "nixpkgs_2"
       },
       "locked": {
         "lastModified": 1635444951,
@@ -124,16 +118,16 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1641578038,
-        "narHash": "sha256-fE5tYnyxiAmgg4qJp7jcHxGcQIazhLY2AI89SInxOck=",
+        "lastModified": 1641528457,
+        "narHash": "sha256-FyU9E63n1W7Ql4pMnhW2/rO9OftWZ37pLppn/c1aisY=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "d89eab1e42717622cfdd5f43f3b99e8680bdb637",
+        "rev": "ff377a78794d412a35245e05428c8f95fef3951f",
         "type": "github"
       },
       "original": {
         "owner": "nixos",
-        "ref": "release-21.11",
+        "ref": "nixos-unstable",
         "repo": "nixpkgs",
         "type": "github"
       }
@@ -186,6 +180,36 @@
       }
     },
     "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1641550923,
+        "narHash": "sha256-vKd+7BWjZO6/p8kdP+szOfecJBw/zbWUWhNNoOx2PUU=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "9bc01c54624b128a9533f912849cd7f2d2bab9f2",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
+    "nixpkgs_3": {
+      "locked": {
+        "lastModified": 1641578038,
+        "narHash": "sha256-fE5tYnyxiAmgg4qJp7jcHxGcQIazhLY2AI89SInxOck=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "d89eab1e42717622cfdd5f43f3b99e8680bdb637",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "release-21.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_4": {
       "locked": {
         "lastModified": 1637209424,
         "narHash": "sha256-oXw75hkCOVtoB+CEElWiTmkC1gNdL3jf0tG2GInytHA=",
@@ -201,7 +225,7 @@
         "type": "github"
       }
     },
-    "nixpkgs_3": {
+    "nixpkgs_5": {
       "locked": {
         "lastModified": 1638097282,
         "narHash": "sha256-EXCzj9b8X/lqDPJapxZThIOKL5ASbpsJZ+8L1LnY1ig=",
@@ -217,7 +241,7 @@
         "type": "github"
       }
     },
-    "nixpkgs_4": {
+    "nixpkgs_6": {
       "locked": {
         "lastModified": 1639061333,
         "narHash": "sha256-rG04piqc/mCGM+6IU0o1JRlH+iqwOXbuuqA1Wtszexw=",
@@ -256,7 +280,7 @@
         "heliwatch": "heliwatch",
         "naersk": "naersk_2",
         "nixos-hardware": "nixos-hardware",
-        "nixpkgs": "nixpkgs",
+        "nixpkgs": "nixpkgs_3",
         "nixpkgs-mobilizon": "nixpkgs-mobilizon",
         "nixpkgs-unstable": "nixpkgs-unstable",
         "scrapers": "scrapers",
@@ -321,7 +345,7 @@
     },
     "secrets": {
       "inputs": {
-        "nixpkgs": "nixpkgs_2",
+        "nixpkgs": "nixpkgs_4",
         "sops-nix": [
           "sops-nix"
         ]
@@ -342,7 +366,7 @@
     },
     "sops-nix": {
       "inputs": {
-        "nixpkgs": "nixpkgs_3"
+        "nixpkgs": "nixpkgs_5"
       },
       "locked": {
         "lastModified": 1641374494,
@@ -444,7 +468,7 @@
     },
     "zentralwerk": {
       "inputs": {
-        "nixpkgs": "nixpkgs_4",
+        "nixpkgs": "nixpkgs_6",
         "nixpkgs-master": "nixpkgs-master",
         "openwrt": "openwrt"
       },
diff --git a/flake.nix b/flake.nix
index 147b3301..3158cd7a 100644
--- a/flake.nix
+++ b/flake.nix
@@ -241,6 +241,13 @@
           system = "x86_64-linux";
         };
 
+        nix-build = nixosSystem' {
+          modules = [
+            ./hosts/containers/nix-build
+          ];
+          system = "x86_64-linux";
+        };
+
         pulsebert = nixosSystem' {
           modules = [
             "${inputs.nixpkgs}/nixos/modules/installer/sd-card/sd-image-aarch64.nix"
diff --git a/host-registry.nix b/host-registry.nix
index c479fe89..0977a649 100644
--- a/host-registry.nix
+++ b/host-registry.nix
@@ -123,6 +123,8 @@ rec {
     gitea.publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIM8MmjiiRmiyUqRYs5a07m7qKDwxh2NwvS2h7pm2b+zx";
 
     dacbert.ip4 = "dacbert.hq.c3d2.de";
+
+    nix-build.ip4 = "172.22.99.156";
   };
 
   hqGlobal = builtins.attrNames hosts;
diff --git a/hosts/containers/nix-build/configuration.nix b/hosts/containers/nix-build/default.nix
similarity index 75%
rename from hosts/containers/nix-build/configuration.nix
rename to hosts/containers/nix-build/default.nix
index fc5ac813..7c866211 100644
--- a/hosts/containers/nix-build/configuration.nix
+++ b/hosts/containers/nix-build/default.nix
@@ -1,6 +1,18 @@
-{ config, pkgs, ... }:
+{ hostRegistry, zentralwerk, config, pkgs, lib, ... }:
 
 {
+  networking.hostName = "nix-build"; # Define your hostname.
+  networking.useDHCP = false;
+  networking.interfaces.enp6s18 = {
+    ipv4.addresses = [{
+      address = hostRegistry.hosts.nix-build.ip4;
+      prefixLength = zentralwerk.lib.config.site.net.c3d2.subnet4Len;
+    }];
+    useDHCP = false;
+  };
+  networking.defaultGateway = "172.22.99.1";
+  networking.firewall.allowedTCPPorts = [ 22 ];
+  
   imports = [
     ./hardware-configuration.nix
   ];
@@ -21,23 +33,15 @@
   nix = {
     buildCores = 40;
     maxJobs = 4;
-    package = pkgs.nixUnstable;
+    package = lib.mkForce pkgs.nixUnstable;
     trustedUsers = [ "client" ];
     extraOptions = ''
       builders-use-substitutes = true
     '';
   };
 
-  networking.hostName = "nix-build"; # Define your hostname.
 
   # time.timeZone = "Europe/Amsterdam";
-
-  # The global useDHCP flag is deprecated, therefore explicitly set to false here.
-  # Per-interface useDHCP will be mandatory in the future, so this generated config
-  # replicates the default behaviour.
-  networking.useDHCP = false;
-  networking.interfaces.enp6s18.useDHCP = true;
-
   environment.systemPackages = with pkgs; [
     wget
     vim
@@ -45,9 +49,7 @@
   ];
 
   services.openssh.enable = true;
-  services.openssh.permitRootLogin = "yes";
-
-  networking.firewall.allowedTCPPorts = [ 22 ];
+  services.openssh.permitRootLogin = lib.mkForce "yes";
 
   # This value determines the NixOS release from which the default
   # settings for stateful data, like file locations and database versions