diff --git a/nixos/config/balthasar.nix b/nixos/config/balthasar.nix
index 622e5e4..353bff9 100644
--- a/nixos/config/balthasar.nix
+++ b/nixos/config/balthasar.nix
@@ -1,3 +1,9 @@
 { self, ... }: { lib, config, pkgs, ... }: {
   imports = with self.nixosModules; [ magi ];
+
+  services.ntpd-rs.settings.source = map (address: {
+    mode = "server";
+    inherit address;
+  }) [ "casper.nyantec.com" "melchior.nyantec.com" ]
+  |> lib.mkAfter;
 }
diff --git a/nixos/config/casper.nix b/nixos/config/casper.nix
index d795d69..abff8d5 100644
--- a/nixos/config/casper.nix
+++ b/nixos/config/casper.nix
@@ -9,4 +9,10 @@
       fsType = "vfat";
     };
   };
+
+  services.ntpd-rs.settings.source = map (address: {
+    mode = "server";
+    inherit address;
+  }) [ "melchior.nyantec.com" "balthasar.nyantec.com" ]
+  |> lib.mkAfter;
 }
diff --git a/nixos/config/melchior.nix b/nixos/config/melchior.nix
index 622e5e4..d2d243e 100644
--- a/nixos/config/melchior.nix
+++ b/nixos/config/melchior.nix
@@ -1,3 +1,9 @@
 { self, ... }: { lib, config, pkgs, ... }: {
   imports = with self.nixosModules; [ magi ];
+
+  services.ntpd-rs.settings.source = map (address: {
+    mode = "server";
+    inherit address;
+  }) [ "casper.nyantec.com" "balthasar.nyantec.com" ]
+  |> lib.mkAfter;
 }
diff --git a/nixos/module/magi.nix b/nixos/module/magi.nix
index dd31743..a412a42 100644
--- a/nixos/module/magi.nix
+++ b/nixos/module/magi.nix
@@ -132,4 +132,28 @@
       ];
     };
   };
+
+  services.ntpd-rs = {
+    enable = true;
+    settings = {
+      source = map (n: {
+        mode = "server";
+        address = "ptbtime${toString n}.ptb.de";
+      }) (lib.range 1 4) ++ [
+        {
+          mode = "server";
+          address = "alucard.nyantec.com";
+        }
+      ];
+
+      server = [
+        {
+          listen = "[::]:123";
+        }
+        {
+          listen = "0.0.0.0:123";
+        }
+      ];
+    };
+  };
 }