diff --git a/pkg/apis/core/v1alpha1/hardware_types.go b/pkg/apis/core/v1alpha1/hardware_types.go
index 5b1037cb4..35558fdbe 100644
--- a/pkg/apis/core/v1alpha1/hardware_types.go
+++ b/pkg/apis/core/v1alpha1/hardware_types.go
@@ -31,6 +31,7 @@ type HardwareList struct {
 // +kubebuilder:resource:path=hardware,scope=Namespaced,categories=tinkerbell,singular=hardware,shortName=hw
 // +kubebuilder:storageversion
 // +kubebuilder:printcolumn:JSONPath=".status.state",name=State,type=string
+// +kubebuilder:validation:JSONPath=".spec.interfaces.dhcp.mac":Pattern=([0-9a-f]{2}[:]){5}([0-9a-f]{2})
 
 // Hardware is the Schema for the Hardware API.
 type Hardware struct {