diff --git a/ops/nixos/howl/default.nix b/ops/nixos/howl/default.nix
index 3e76475bed..b1f2d75abf 100644
--- a/ops/nixos/howl/default.nix
+++ b/ops/nixos/howl/default.nix
@@ -70,6 +70,7 @@ in {
   security.polkit.enable = true;
 
   networking.hostName = "howl";
+  networking.domain = "int.as205479.net";
   networking.hostId = "cdd51451";
 
   # Boot faster.
diff --git a/ops/nixos/laputa/default.nix b/ops/nixos/laputa/default.nix
index a42a0a95cf..c8c656fd28 100644
--- a/ops/nixos/laputa/default.nix
+++ b/ops/nixos/laputa/default.nix
@@ -80,6 +80,7 @@
   security.polkit.enable = true;
 
   networking.hostName = "laputa";
+  networking.domain = "int.as205479.net";
   networking.hostId = "88b46fc6";
 
   # Boot faster.
diff --git a/ops/nixos/porcorosso/default.nix b/ops/nixos/porcorosso/default.nix
index e21f7d4049..35c79bd8fb 100644
--- a/ops/nixos/porcorosso/default.nix
+++ b/ops/nixos/porcorosso/default.nix
@@ -125,6 +125,7 @@ in {
   security.polkit.enable = true;
 
   networking.hostName = "porcorosso";
+  networking.domain = "int.as205479.net";
   networking.hostId = "1ee729a4";
 
   # Boot faster.