diff --git a/nixos/modules/services/networking/keepalived/vrrp-instance-options.nix b/nixos/modules/services/networking/keepalived/vrrp-instance-options.nix
index 5d69963d2047..35401d439a91 100644
--- a/nixos/modules/services/networking/keepalived/vrrp-instance-options.nix
+++ b/nixos/modules/services/networking/keepalived/vrrp-instance-options.nix
@@ -22,7 +22,7 @@ with lib;
     };
 
     virtualRouterId = mkOption {
-      type = types.int;
+      type = types.ints.between 1 255;
       description = lib.mdDoc ''
         Arbitrary unique number 1..255. Used to differentiate multiple instances
         of vrrpd running on the same NIC (and hence same socket).