diff --git a/src/main/java/net/hostsharing/hsadminng/hs/booking/item/validators/HsDomainSetupBookingItemValidator.java b/src/main/java/net/hostsharing/hsadminng/hs/booking/item/validators/HsDomainSetupBookingItemValidator.java
index 5c12d21a..69b9bf17 100644
--- a/src/main/java/net/hostsharing/hsadminng/hs/booking/item/validators/HsDomainSetupBookingItemValidator.java
+++ b/src/main/java/net/hostsharing/hsadminng/hs/booking/item/validators/HsDomainSetupBookingItemValidator.java
@@ -1,10 +1,13 @@
 
 package net.hostsharing.hsadminng.hs.booking.item.validators;
 
+import net.hostsharing.hsadminng.hs.booking.item.HsBookingItem;
 import net.hostsharing.hsadminng.hs.validation.PropertiesProvider;
 
 import jakarta.persistence.EntityManager;
 import java.security.SecureRandom;
+import java.util.ArrayList;
+import java.util.List;
 
 import static net.hostsharing.hsadminng.hs.hosting.asset.validators.Dns.REGISTRAR_LEVEL_DOMAINS;
 import static net.hostsharing.hsadminng.hs.validation.StringProperty.stringProperty;
@@ -32,6 +35,19 @@ class HsDomainSetupBookingItemValidator extends HsBookingItemEntityValidator {
         );
     }
 
+    @Override
+    public List<String> validateEntity(final HsBookingItem bookingItem) {
+        final var violations = new ArrayList<String>();
+        final var domainName = bookingItem.getDirectValue(DOMAIN_NAME_PROPERTY_NAME, String.class);
+        if (!bookingItem.isLoaded() &&
+                domainName.matches("hostsharing.(com|net|org|coop|de)")) {
+            violations.add("'" + bookingItem.toShortString() + ".resources." + DOMAIN_NAME_PROPERTY_NAME + "' = '" + domainName
+                    + "' is a forbidden Hostsharing domain name");
+        }
+        violations.addAll(super.validateEntity(bookingItem));
+        return violations;
+    }
+
     private static String generateVerificationCode(final EntityManager em, final PropertiesProvider propertiesProvider) {
         final var userDefinedVerificationCode = propertiesProvider.getDirectValue(VERIFICATION_CODE_PROPERTY_NAME, String.class);
         if (userDefinedVerificationCode != null) {