doc/hs-hosting-asset-type-structure.md

@@ -1,6 +1,61 @@
 ## HostingAsset Type Structure
 
 
+### Server+Webspace
+
+```plantuml
+@startuml
+left to right direction
+
+package Booking #feb28c {
+    entity BI_PRIVATE_CLOUD
+    entity BI_CLOUD_SERVER
+    entity BI_MANAGED_SERVER
+    entity BI_MANAGED_WEBSPACE
+}
+
+package Hosting #feb28c{
+    package Server #99bcdb {
+        entity HA_CLOUD_SERVER
+        entity HA_MANAGED_SERVER
+        entity HA_IPV4_NUMBER
+        entity HA_IPV6_NUMBER
+    }
+
+    package Webspace #99bcdb {
+        entity HA_MANAGED_WEBSPACE
+        entity HA_UNIX_USER
+        entity HA_EMAIL_ALIAS
+    }
+
+}
+
+BI_CLOUD_SERVER *--> BI_PRIVATE_CLOUD
+BI_MANAGED_SERVER *--> BI_PRIVATE_CLOUD
+BI_MANAGED_WEBSPACE *--> BI_MANAGED_SERVER
+
+HA_CLOUD_SERVER *==> BI_CLOUD_SERVER
+HA_MANAGED_SERVER *==> BI_MANAGED_SERVER
+HA_MANAGED_WEBSPACE *==> BI_MANAGED_WEBSPACE
+HA_MANAGED_WEBSPACE o..> HA_MANAGED_SERVER
+HA_UNIX_USER *==> HA_MANAGED_WEBSPACE
+HA_EMAIL_ALIAS *==> HA_MANAGED_WEBSPACE
+HA_IPV4_NUMBER o..> HA_CLOUD_SERVER
+HA_IPV4_NUMBER o..> HA_MANAGED_SERVER
+HA_IPV4_NUMBER o..> HA_MANAGED_WEBSPACE
+HA_IPV6_NUMBER o..> HA_CLOUD_SERVER
+HA_IPV6_NUMBER o..> HA_MANAGED_SERVER
+HA_IPV6_NUMBER o..> HA_MANAGED_WEBSPACE
+
+package Legend #white {
+    SUB_ENTITY1 *--> REQUIRED_PARENT_ENTITY
+    SUB_ENTITY2 *..> OPTIONAL_PARENT_ENTITY
+    ASSIGNED_ENTITY1 o--> REQUIRED_ASSIGNED_TO_ENTITY1
+    ASSIGNED_ENTITY2 o..> OPTIONAL_ASSIGNED_TO_ENTITY2
+}
+Booking -down[hidden]->Legend
+```
+
 ### Domain
 
 ```plantuml
@@ -24,12 +79,6 @@ package Hosting #feb28c{
         entity HA_EMAIL_ADDRESS
     }
 
-    package Server #99bcdb {
-        entity HA_CLOUD_SERVER
-        entity HA_MANAGED_SERVER
-        entity HA_IP_NUMBER
-    }
-
     package Webspace #99bcdb {
         entity HA_MANAGED_WEBSPACE
         entity HA_UNIX_USER
@@ -42,25 +91,19 @@ BI_CLOUD_SERVER *--> BI_PRIVATE_CLOUD
 BI_MANAGED_SERVER *--> BI_PRIVATE_CLOUD
 BI_MANAGED_WEBSPACE *--> BI_MANAGED_SERVER
 
-HA_CLOUD_SERVER *==> BI_CLOUD_SERVER
-HA_MANAGED_SERVER *==> BI_MANAGED_SERVER
 HA_MANAGED_WEBSPACE *==> BI_MANAGED_WEBSPACE
-HA_MANAGED_WEBSPACE o..> HA_MANAGED_SERVER
 HA_UNIX_USER *==> HA_MANAGED_WEBSPACE
 HA_EMAIL_ALIAS *==> HA_MANAGED_WEBSPACE
 HA_DOMAIN_SETUP o..> HA_DOMAIN_SETUP
 HA_DOMAIN_DNS_SETUP *==> HA_DOMAIN_SETUP
-HA_DOMAIN_DNS_SETUP o..> HA_MANAGED_WEBSPACE
+HA_DOMAIN_DNS_SETUP o--> HA_MANAGED_WEBSPACE
 HA_DOMAIN_HTTP_SETUP *==> HA_DOMAIN_SETUP
-HA_DOMAIN_HTTP_SETUP o..> HA_UNIX_USER
+HA_DOMAIN_HTTP_SETUP o--> HA_UNIX_USER
 HA_DOMAIN_SMTP_SETUP *==> HA_DOMAIN_SETUP
-HA_DOMAIN_SMTP_SETUP o..> HA_MANAGED_WEBSPACE
+HA_DOMAIN_SMTP_SETUP o--> HA_MANAGED_WEBSPACE
 HA_DOMAIN_MBOX_SETUP *==> HA_DOMAIN_SETUP
-HA_DOMAIN_MBOX_SETUP o..> HA_MANAGED_WEBSPACE
+HA_DOMAIN_MBOX_SETUP o--> HA_MANAGED_WEBSPACE
 HA_EMAIL_ADDRESS *==> HA_DOMAIN_MBOX_SETUP
-HA_IP_NUMBER o..> HA_CLOUD_SERVER
-HA_IP_NUMBER o..> HA_MANAGED_SERVER
-HA_IP_NUMBER o..> HA_MANAGED_WEBSPACE
 
 package Legend #white {
     SUB_ENTITY1 *--> REQUIRED_PARENT_ENTITY
@@ -91,12 +134,6 @@ package Hosting #feb28c{
         entity HA_MARIADB_DATABASE
     }
 
-    package Server #99bcdb {
-        entity HA_CLOUD_SERVER
-        entity HA_MANAGED_SERVER
-        entity HA_IP_NUMBER
-    }
-
     package Webspace #99bcdb {
         entity HA_MANAGED_WEBSPACE
         entity HA_UNIX_USER
@@ -109,20 +146,12 @@ BI_CLOUD_SERVER *--> BI_PRIVATE_CLOUD
 BI_MANAGED_SERVER *--> BI_PRIVATE_CLOUD
 BI_MANAGED_WEBSPACE *--> BI_MANAGED_SERVER
 
-HA_CLOUD_SERVER *==> BI_CLOUD_SERVER
-HA_MANAGED_SERVER *==> BI_MANAGED_SERVER
 HA_MANAGED_WEBSPACE *==> BI_MANAGED_WEBSPACE
-HA_MANAGED_WEBSPACE o..> HA_MANAGED_SERVER
 HA_UNIX_USER *==> HA_MANAGED_WEBSPACE
 HA_EMAIL_ALIAS *==> HA_MANAGED_WEBSPACE
-HA_MARIADB_INSTANCE *==> HA_MANAGED_SERVER
 HA_MARIADB_USER *==> HA_MANAGED_WEBSPACE
-HA_MARIADB_USER o..> HA_MARIADB_INSTANCE
+HA_MARIADB_USER o--> HA_MARIADB_INSTANCE
 HA_MARIADB_DATABASE *==> HA_MARIADB_USER
-HA_MARIADB_DATABASE o..> HA_MARIADB_INSTANCE
-HA_IP_NUMBER o..> HA_CLOUD_SERVER
-HA_IP_NUMBER o..> HA_MANAGED_SERVER
-HA_IP_NUMBER o..> HA_MANAGED_WEBSPACE
 
 package Legend #white {
     SUB_ENTITY1 *--> REQUIRED_PARENT_ENTITY
@@ -153,12 +182,6 @@ package Hosting #feb28c{
         entity HA_PGSQL_DATABASE
     }
 
-    package Server #99bcdb {
-        entity HA_CLOUD_SERVER
-        entity HA_MANAGED_SERVER
-        entity HA_IP_NUMBER
-    }
-
     package Webspace #99bcdb {
         entity HA_MANAGED_WEBSPACE
         entity HA_UNIX_USER
@@ -171,20 +194,12 @@ BI_CLOUD_SERVER *--> BI_PRIVATE_CLOUD
 BI_MANAGED_SERVER *--> BI_PRIVATE_CLOUD
 BI_MANAGED_WEBSPACE *--> BI_MANAGED_SERVER
 
-HA_CLOUD_SERVER *==> BI_CLOUD_SERVER
-HA_MANAGED_SERVER *==> BI_MANAGED_SERVER
 HA_MANAGED_WEBSPACE *==> BI_MANAGED_WEBSPACE
-HA_MANAGED_WEBSPACE o..> HA_MANAGED_SERVER
 HA_UNIX_USER *==> HA_MANAGED_WEBSPACE
 HA_EMAIL_ALIAS *==> HA_MANAGED_WEBSPACE
-HA_PGSQL_INSTANCE *==> HA_MANAGED_SERVER
+HA_PGSQL_USER *==> HA_MANAGED_WEBSPACE
-HA_PGSQL_USER *==> HA_PGSQL_INSTANCE
+HA_PGSQL_USER o--> HA_PGSQL_INSTANCE
-HA_PGSQL_USER o..> HA_MANAGED_WEBSPACE
+HA_PGSQL_DATABASE *==> HA_PGSQL_USER
-HA_PGSQL_DATABASE *==> HA_MANAGED_WEBSPACE
-HA_PGSQL_DATABASE o..> HA_PGSQL_INSTANCE
-HA_IP_NUMBER o..> HA_CLOUD_SERVER
-HA_IP_NUMBER o..> HA_MANAGED_SERVER
-HA_IP_NUMBER o..> HA_MANAGED_WEBSPACE
 
 package Legend #white {
     SUB_ENTITY1 *--> REQUIRED_PARENT_ENTITY

src/main/java/net/hostsharing/hsadminng/hs/booking/item/HsBookingItemType.java

@@ -1,6 +1,7 @@
 package net.hostsharing.hsadminng.hs.booking.item;
 
 import java.util.List;
+import java.util.Set;
 
 import static java.util.Optional.ofNullable;
 
@@ -21,12 +22,17 @@ public enum HsBookingItemType implements Node {
     }
 
     @Override
-    public List<String> edges() {
+    public List<String> edges(final Set<String> inGroups) {
         return ofNullable(parentItemType)
                 .map(p -> (nodeName() + " *--> " + p.nodeName()))
                 .stream().toList();
     }
 
+    @Override
+    public boolean belongsToAny(final Set<String> groups) {
+        return true; // we currently do not filter booking item types
+    }
+
     @Override
     public String nodeName() {
         return "BI_" + name();

src/main/java/net/hostsharing/hsadminng/hs/booking/item/Node.java

@@ -1,9 +1,11 @@
 package net.hostsharing.hsadminng.hs.booking.item;
 
 import java.util.List;
+import java.util.Set;
 
 public interface Node {
 
     String nodeName();
-    List<String> edges();
+    boolean belongsToAny(Set<String> groups);
+    List<String> edges(final Set<String> inGroup);
 }

src/main/java/net/hostsharing/hsadminng/hs/hosting/asset/HsHostingAssetType.java

@@ -10,6 +10,7 @@ import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
 import java.util.Set;
@@ -18,7 +19,11 @@ import java.util.function.Function;
 import static java.util.Arrays.stream;
 import static java.util.stream.Collectors.joining;
 import static java.util.stream.Collectors.toSet;
-import static net.hostsharing.hsadminng.hs.hosting.asset.EntityTypeRelation.*;
+import static net.hostsharing.hsadminng.hs.hosting.asset.EntityTypeRelation.assignedTo;
+import static net.hostsharing.hsadminng.hs.hosting.asset.EntityTypeRelation.optionalParent;
+import static net.hostsharing.hsadminng.hs.hosting.asset.EntityTypeRelation.optionallyAssignedTo;
+import static net.hostsharing.hsadminng.hs.hosting.asset.EntityTypeRelation.requiredParent;
+import static net.hostsharing.hsadminng.hs.hosting.asset.EntityTypeRelation.requires;
 import static net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType.RelationPolicy.OPTIONAL;
 import static net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType.RelationPolicy.REQUIRED;
 import static net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType.RelationType.ASSIGNED_TO_ASSET;
@@ -106,11 +111,14 @@ public enum HsHostingAssetType implements Node {
             inGroup("MariaDB"),
             requiredParent(MARIADB_USER)), // thus, the MARIADB_USER:Agent becomes RBAC owner
 
-    IP_NUMBER(
+    IPV4_NUMBER(
             inGroup("Server"),
-            assignedTo(CLOUD_SERVER),
+            optionallyAssignedTo(CLOUD_SERVER).or(MANAGED_SERVER).or(MANAGED_WEBSPACE)
-            assignedTo(MANAGED_SERVER),
+    ),
-            assignedTo(MANAGED_WEBSPACE)
+
+    IPV6_NUMBER(
+            inGroup("Server"),
+            optionallyAssignedTo(CLOUD_SERVER).or(MANAGED_SERVER).or(MANAGED_WEBSPACE)
     );
 
     private final String groupName;
@@ -144,44 +152,50 @@ public enum HsHostingAssetType implements Node {
                 .orElse(RelationPolicy.FORBIDDEN);
     }
 
-    public HsBookingItemType bookingItemType() {
+    public Set<HsBookingItemType> bookingItemTypes() {
         return stream(relations)
                 .filter(r -> r.relationType == BOOKING_ITEM)
-                .map(r -> HsBookingItemType.valueOf(r.relatedType(this).toString()))
                 .reduce(HsHostingAssetType::onlyASingleElementExpectedException)
-                .orElse(null);
+                .map(r -> r.relatedTypes(this))
+                .stream().flatMap(Set::stream)
+                .map(r -> (HsBookingItemType) r)
+                .collect(toSet());
     }
 
     public RelationPolicy parentAssetPolicy() {
         return stream(relations)
                 .filter(r -> r.relationType == PARENT_ASSET)
-                .map(r -> r.relationPolicy)
                 .reduce(HsHostingAssetType::onlyASingleElementExpectedException)
+                .map(r -> r.relationPolicy)
                 .orElse(RelationPolicy.FORBIDDEN);
     }
 
-    public HsHostingAssetType parentAssetType() {
+    public Set<HsHostingAssetType> parentAssetTypes() {
         return stream(relations)
                 .filter(r -> r.relationType == PARENT_ASSET)
-                .map(r -> HsHostingAssetType.valueOf(r.relatedType(this).toString()))
                 .reduce(HsHostingAssetType::onlyASingleElementExpectedException)
-                .orElse(null);
+                .map(r -> r.relatedTypes(this))
+                .stream().flatMap(Set::stream)
+                .map(r -> (HsHostingAssetType) r)
+                .collect(toSet());
     }
 
     public RelationPolicy assignedToAssetPolicy() {
         return stream(relations)
                 .filter(r -> r.relationType == ASSIGNED_TO_ASSET)
-                .map(r -> r.relationPolicy)
                 .reduce(HsHostingAssetType::onlyASingleElementExpectedException)
+                .map(r -> r.relationPolicy)
                 .orElse(RelationPolicy.FORBIDDEN);
     }
 
-    public HsHostingAssetType assignedToAssetType() {
+    public Set<HsHostingAssetType> assignedToAssetTypes() {
         return stream(relations)
                 .filter(r -> r.relationType == ASSIGNED_TO_ASSET)
-                .map(r -> HsHostingAssetType.valueOf(r.relatedType(this).toString()))
                 .reduce(HsHostingAssetType::onlyASingleElementExpectedException)
-                .orElse(null);
+                .map(r -> r.relatedTypes(this))
+                .stream().flatMap(Set::stream)
+                .map(r -> (HsHostingAssetType) r)
+                .collect(toSet());
     }
 
     private static <X> X onlyASingleElementExpectedException(Object a, Object b) {
@@ -189,12 +203,22 @@ public enum HsHostingAssetType implements Node {
     }
 
     @Override
-    public List<String> edges() {
+    public List<String> edges(final Set<String> inGroups) {
         return stream(relations)
-                .map(r -> nodeName() + r.edge + r.relatedType(this).nodeName())
+                .map(r -> r.relatedTypes(this).stream()
+                        .filter(x -> x.belongsToAny(inGroups))
+                        .map(x -> nodeName() + r.edge + x.nodeName())
+                        .toList())
+                .flatMap(List::stream)
+                .sorted()
                 .toList();
     }
 
+    @Override
+    public boolean belongsToAny(final Set<String> groups) {
+        return groups.contains(this.groupName);
+    }
+
     @Override
     public String nodeName() {
         return "HA_" + name();
@@ -220,12 +244,12 @@ public enum HsHostingAssetType implements Node {
                 .map(t -> "entity " + t.nodeName())
                 .collect(joining("\n"));
         final String bookingItemEdges = stream(HsBookingItemType.values())
-                .map(HsBookingItemType::edges)
+                .map(t -> t.edges(includedHostingGroups))
                 .flatMap(Collection::stream)
                 .collect(joining("\n"));
         final String hostingAssetEdges = stream(HsHostingAssetType.values())
                 .filter(t -> t.isInGroups(includedHostingGroups))
-                .map(HsHostingAssetType::edges)
+                .map(t -> t.edges(includedHostingGroups))
                 .flatMap(Collection::stream)
                 .collect(joining("\n"));
         return """
@@ -291,9 +315,11 @@ public enum HsHostingAssetType implements Node {
                 .map(t -> t.groupName)
                 .collect(toSet()));
 
-        markdown.append(renderAsPlantUML("Domain", Set.of("Domain", "Webspace", "Server")))
+        markdown
-                .append(renderAsPlantUML("MariaDB", Set.of("MariaDB", "Webspace", "Server")))
+                .append(renderAsPlantUML("Server+Webspace", Set.of("Server", "Webspace")))
-                .append(renderAsPlantUML("PostgreSQL", Set.of("PostgreSQL", "Webspace", "Server")));
+                .append(renderAsPlantUML("Domain", Set.of("Domain", "Webspace")))
+                .append(renderAsPlantUML("MariaDB", Set.of("MariaDB", "Webspace")))
+                .append(renderAsPlantUML("PostgreSQL", Set.of("PostgreSQL", "Webspace")));
 
         markdown.append("""
 
@@ -328,27 +354,78 @@ class EntityTypeRelation<E, T extends Node> {
     final HsHostingAssetType.RelationPolicy relationPolicy;
     final HsHostingAssetType.RelationType relationType;
     final Function<HsHostingAssetEntity, E> getter;
-    private final T relatedType;
+    private final List<T> acceptedRelatedTypes;
     final String edge;
 
-    public T relatedType(final HsHostingAssetType referringType) {
+    private EntityTypeRelation(
+            final HsHostingAssetType.RelationPolicy relationPolicy,
+            final HsHostingAssetType.RelationType relationType,
+            final Function<HsHostingAssetEntity, E> getter,
+            final T acceptedRelatedType,
+            final String edge
+    ) {
+        this(relationPolicy, relationType, getter, modifiyableListOf(acceptedRelatedType), edge);
+    }
+
+    public <R extends Node> Set<R> relatedTypes(final HsHostingAssetType referringType) {
+        final Set<Node> result = acceptedRelatedTypes.stream()
+                .map(t -> t == HsHostingAssetType.SAME_TYPE ? referringType : t)
+                .collect(toSet());
         //noinspection unchecked
-        return relatedType == HsHostingAssetType.SAME_TYPE ? (T) referringType : relatedType;
+        return (Set<R>) result;
     }
 
     static EntityTypeRelation<HsBookingItemEntity, HsBookingItemType> requires(final HsBookingItemType bookingItemType) {
-        return new EntityTypeRelation<>(REQUIRED, BOOKING_ITEM, HsHostingAssetEntity::getBookingItem, bookingItemType, " *==> ");
+        return new EntityTypeRelation<>(
+                REQUIRED,
+                BOOKING_ITEM,
+                HsHostingAssetEntity::getBookingItem,
+                bookingItemType,
+                " *==> ");
     }
 
     static EntityTypeRelation<HsHostingAssetEntity, HsHostingAssetType> optionalParent(final HsHostingAssetType hostingAssetType) {
-        return new EntityTypeRelation<>(OPTIONAL, PARENT_ASSET, HsHostingAssetEntity::getParentAsset, hostingAssetType, " o..> ");
+        return new EntityTypeRelation<>(
+                OPTIONAL,
+                PARENT_ASSET,
+                HsHostingAssetEntity::getParentAsset,
+                hostingAssetType,
+                " o..> ");
     }
 
     static EntityTypeRelation<HsHostingAssetEntity, HsHostingAssetType> requiredParent(final HsHostingAssetType hostingAssetType) {
-        return new EntityTypeRelation<>(REQUIRED, PARENT_ASSET, HsHostingAssetEntity::getParentAsset, hostingAssetType, " *==> ");
+        return new EntityTypeRelation<>(
+                REQUIRED,
+                PARENT_ASSET,
+                HsHostingAssetEntity::getParentAsset,
+                hostingAssetType,
+                " *==> ");
     }
 
     static EntityTypeRelation<HsHostingAssetEntity, HsHostingAssetType> assignedTo(final HsHostingAssetType hostingAssetType) {
-        return new EntityTypeRelation<>(REQUIRED, ASSIGNED_TO_ASSET, HsHostingAssetEntity::getAssignedToAsset, hostingAssetType, " o..> ");
+        return new EntityTypeRelation<>(
+                REQUIRED,
+                ASSIGNED_TO_ASSET,
+                HsHostingAssetEntity::getAssignedToAsset,
+                hostingAssetType,
+                " o--> ");
+    }
+
+    EntityTypeRelation<E, T> or(final T alternativeHostingAssetType) {
+        acceptedRelatedTypes.add(alternativeHostingAssetType);
+        return this;
+    }
+
+    static EntityTypeRelation<HsHostingAssetEntity, HsHostingAssetType> optionallyAssignedTo(final HsHostingAssetType hostingAssetType) {
+        return new EntityTypeRelation<>(
+                OPTIONAL,
+                ASSIGNED_TO_ASSET,
+                HsHostingAssetEntity::getAssignedToAsset,
+                hostingAssetType,
+                " o..> ");
+    }
+
+    private static <T extends Node> ArrayList<T> modifiyableListOf(final T acceptedRelatedType) {
+        return new ArrayList<>(List.of(acceptedRelatedType));
     }
 }

src/main/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HostingAssetEntityValidator.java

@@ -12,9 +12,11 @@ import net.hostsharing.hsadminng.hs.validation.ValidatableProperty;
 import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
+import java.util.Set;
 import java.util.function.BiFunction;
 import java.util.function.Function;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 import static java.util.Arrays.stream;
@@ -37,17 +39,17 @@ public abstract class HostingAssetEntityValidator extends HsEntityValidator<HsHo
         super(properties);
         this.bookingItemReferenceValidation = new ReferenceValidator<>(
                 assetType.bookingItemPolicy(),
-                assetType.bookingItemType(),
+                assetType.bookingItemTypes(),
                 HsHostingAssetEntity::getBookingItem,
                 HsBookingItemEntity::getType);
         this.parentAssetReferenceValidation = new ReferenceValidator<>(
                 assetType.parentAssetPolicy(),
-                assetType.parentAssetType(),
+                assetType.parentAssetTypes(),
                 HsHostingAssetEntity::getParentAsset,
                 HsHostingAssetEntity::getType);
         this.assignedToAssetReferenceValidation = new ReferenceValidator<>(
                 assetType.assignedToAssetPolicy(),
-                assetType.assignedToAssetType(),
+                assetType.assignedToAssetTypes(),
                 HsHostingAssetEntity::getAssignedToAsset,
                 HsHostingAssetEntity::getType);
         this.alarmContactValidation = alarmContactValidation;
@@ -154,17 +156,17 @@ public abstract class HostingAssetEntityValidator extends HsEntityValidator<HsHo
     static class ReferenceValidator<S, T> {
 
         private final HsHostingAssetType.RelationPolicy policy;
-        private final T referencedEntityType;
+        private final Set<T> referencedEntityTypes;
         private final Function<HsHostingAssetEntity, S> referencedEntityGetter;
         private final Function<S, T> referencedEntityTypeGetter;
 
         public ReferenceValidator(
                 final HsHostingAssetType.RelationPolicy policy,
-                final T subEntityType,
+                final Set<T> referencedEntityTypes,
                 final Function<HsHostingAssetEntity, S> referencedEntityGetter,
                 final Function<S, T> referencedEntityTypeGetter) {
             this.policy = policy;
-            this.referencedEntityType = subEntityType;
+            this.referencedEntityTypes = referencedEntityTypes;
             this.referencedEntityGetter = referencedEntityGetter;
             this.referencedEntityTypeGetter = referencedEntityTypeGetter;
         }
@@ -173,7 +175,7 @@ public abstract class HostingAssetEntityValidator extends HsEntityValidator<HsHo
                 final HsHostingAssetType.RelationPolicy policy,
                 final Function<HsHostingAssetEntity, S> referencedEntityGetter) {
             this.policy = policy;
-            this.referencedEntityType = null;
+            this.referencedEntityTypes = Set.of();
             this.referencedEntityGetter = referencedEntityGetter;
             this.referencedEntityTypeGetter = e -> null;
         }
@@ -185,15 +187,15 @@ public abstract class HostingAssetEntityValidator extends HsEntityValidator<HsHo
 
             switch (policy) {
             case REQUIRED:
-                if (actualEntityType != referencedEntityType) {
+                if (!referencedEntityTypes.contains(actualEntityType)) {
                     return List.of(actualEntityType == null
-                            ? referenceFieldName + "' must be of type " + referencedEntityType + " but is null"
+                            ? referenceFieldName + "' must be of type " + toDisplay(referencedEntityTypes) + " but is null"
-                            : referenceFieldName + "' must be of type " + referencedEntityType + " but is of type " + actualEntityType);
+                            : referenceFieldName + "' must be of type " + toDisplay(referencedEntityTypes) + " but is of type " + actualEntityType);
                 }
                 break;
             case OPTIONAL:
-                if (actualEntityType != null && actualEntityType != referencedEntityType) {
+                if (actualEntityType != null && !referencedEntityTypes.contains(actualEntityType)) {
-                    return List.of(referenceFieldName + "' must be null or of type " + referencedEntityType + " but is of type "
+                    return List.of(referenceFieldName + "' must be null or of type " + toDisplay(referencedEntityTypes) + " but is of type "
                             + actualEntityType);
                 }
                 break;
@@ -205,6 +207,10 @@ public abstract class HostingAssetEntityValidator extends HsEntityValidator<HsHo
             }
             return emptyList();
         }
+
+        private String toDisplay(final Set<T> referencedEntityTypes) {
+            return referencedEntityTypes.stream().sorted().map(Object::toString).collect(Collectors.joining(" or "));
+        }
     }
 
     static class AlarmContact extends ReferenceValidator<HsOfficeContactEntity, Enum<?>> {

src/main/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HostingAssetEntityValidatorRegistry.java

@@ -32,6 +32,8 @@ public class HostingAssetEntityValidatorRegistry {
         register(PGSQL_INSTANCE, new HsPostgreSqlDbInstanceHostingAssetValidator());
         register(PGSQL_USER, new HsPostgreSqlUserHostingAssetValidator());
         register(PGSQL_DATABASE, new HsPostgreSqlDatabaseHostingAssetValidator());
+        register(IPV4_NUMBER, new HsIPv4NumberHostingAssetValidator());
+        register(IPV6_NUMBER, new HsIPv6NumberHostingAssetValidator());
     }
 
     private static void register(final Enum<HsHostingAssetType> type, final HsEntityValidator<HsHostingAssetEntity> validator) {

src/main/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HsIPv4NumberHostingAssetValidator.java

@@ -0,0 +1,26 @@
+package net.hostsharing.hsadminng.hs.hosting.asset.validators;
+
+import net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetEntity;
+
+import java.util.regex.Pattern;
+
+import static net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType.IPV4_NUMBER;
+
+class HsIPv4NumberHostingAssetValidator extends HostingAssetEntityValidator {
+
+    private static final Pattern IPV4_REGEX = Pattern.compile("^((25[0-5]|(2[0-4]|1\\d|[1-9]|)\\d)\\.?\\b){4}$");
+
+    HsIPv4NumberHostingAssetValidator() {
+        super(
+                IPV4_NUMBER,
+                AlarmContact.isOptional(),
+
+                NO_EXTRA_PROPERTIES
+        );
+    }
+
+    @Override
+    protected Pattern identifierPattern(final HsHostingAssetEntity assetEntity) {
+        return IPV4_REGEX;
+    }
+}

src/main/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HsIPv6NumberHostingAssetValidator.java

@@ -0,0 +1,49 @@
+package net.hostsharing.hsadminng.hs.hosting.asset.validators;
+
+import net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetEntity;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.List;
+import java.util.regex.Pattern;
+
+import static net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType.IPV6_NUMBER;
+
+class HsIPv6NumberHostingAssetValidator extends HostingAssetEntityValidator {
+
+    // simplified pattern, the real check is done by letting Java parse the address
+    private static final Pattern IPV6_REGEX = Pattern.compile("([a-f0-9:]+:+)+[a-f0-9]+");
+
+    HsIPv6NumberHostingAssetValidator() {
+        super(
+                IPV6_NUMBER,
+                AlarmContact.isOptional(),
+
+                NO_EXTRA_PROPERTIES
+        );
+    }
+
+    @Override
+    public List<String> validateEntity(final HsHostingAssetEntity assetEntity) {
+        final var violations = super.validateEntity(assetEntity);
+
+        if (!isValidIPv6Address(assetEntity.getIdentifier())) {
+            violations.add("'identifier' expected to be a valid IPv6 address, but is '" + assetEntity.getIdentifier() + "'");
+        }
+
+        return violations;
+    }
+
+    @Override
+    protected Pattern identifierPattern(final HsHostingAssetEntity assetEntity) {
+        return IPV6_REGEX;
+    }
+
+    private boolean isValidIPv6Address(final String identifier) {
+        try {
+            return InetAddress.getByName(identifier) instanceof java.net.Inet6Address;
+        } catch (UnknownHostException e) {
+            return false;
+        }
+    }
+}

src/main/java/net/hostsharing/hsadminng/mapper/Array.java

@@ -1,6 +1,7 @@
 package net.hostsharing.hsadminng.mapper;
 
 
+
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
@@ -51,6 +52,11 @@ public class Array {
         return of();
     }
 
+    public static <T> T[] emptyArray(final Class<T> elementClass) {
+        //noinspection unchecked
+        return (T[]) java.lang.reflect.Array.newInstance(elementClass, 0);
+    }
+
     @SafeVarargs
     public static <T> T[] insertNewEntriesAfterExistingEntry(final T[] array, final T entryToFind, final T... newEntries) {
         final var arrayList = new ArrayList<>(asList(array));

src/main/resources/api-definition/hs-hosting/hs-hosting-asset-schemas.yaml

@@ -23,6 +23,8 @@ components:
                 - MARIADB_INSTANCE
                 - MARIADB_USER
                 - MARIADB_DATABASE
+                - IPV4_NUMBER
+                - IPV6_NUMBER
 
         HsHostingAsset:
             type: object

src/main/resources/db/changelog/7-hs-hosting/701-hosting-asset/7010-hs-hosting-asset.sql

@@ -21,7 +21,9 @@ create type HsHostingAssetType as enum (
     'PGSQL_DATABASE',
     'MARIADB_INSTANCE',
     'MARIADB_USER',
-    'MARIADB_DATABASE'
+    'MARIADB_DATABASE',
+    'IPV4_NUMBER',
+    'IPV6_NUMBER'
 );
 
 CREATE CAST (character varying as HsHostingAssetType) WITH INOUT AS IMPLICIT;
@@ -85,6 +87,10 @@ begin
         when 'MARIADB_INSTANCE' then 'MANAGED_SERVER'
         when 'MARIADB_USER' then 'MANAGED_WEBSPACE'
         when 'MARIADB_DATABASE' then 'MARIADB_USER'
+
+        when 'IPV4_NUMBER' then null
+        when 'IPV6_NUMBER' then null
+
         else raiseException(format('[400] unknown asset type %s', NEW.type::text))
     end);
 

src/test/java/net/hostsharing/hsadminng/hs/hosting/asset/HsHostingAssetControllerRestTest.java

@@ -488,6 +488,44 @@ public class HsHostingAssetControllerRestTest {
                             }
                         }
                     ]
+                """),
+        IPV4_NUMBER(
+                List.of(
+                        HsHostingAssetEntity.builder()
+                                .type(HsHostingAssetType.IPV4_NUMBER)
+                                .assignedToAsset(TEST_MANAGED_SERVER_HOSTING_ASSET)
+                                .identifier("11.12.13.14")
+                                .caption("some fake IPv4 number")
+                                .build()),
+                """
+                    [
+                        {
+                            "type": "IPV4_NUMBER",
+                            "identifier": "11.12.13.14",
+                            "caption": "some fake IPv4 number",
+                            "alarmContact": null,
+                            "config": {}
+                        }
+                    ]
+                """),
+        IPV6_NUMBER(
+                List.of(
+                        HsHostingAssetEntity.builder()
+                                .type(HsHostingAssetType.IPV6_NUMBER)
+                                .assignedToAsset(TEST_MANAGED_SERVER_HOSTING_ASSET)
+                                .identifier("2001:db8:3333:4444:5555:6666:7777:8888")
+                                .caption("some fake IPv6 number")
+                                .build()),
+                """
+                    [
+                        {
+                            "type": "IPV6_NUMBER",
+                            "identifier": "2001:db8:3333:4444:5555:6666:7777:8888",
+                            "caption": "some fake IPv6 number",
+                            "alarmContact": null,
+                            "config": {}
+                        }
+                    ]
                 """);
 
         final HsHostingAssetType assetType;

src/test/java/net/hostsharing/hsadminng/hs/hosting/asset/HsHostingAssetPropsControllerAcceptanceTest.java

@@ -47,7 +47,9 @@ class HsHostingAssetPropsControllerAcceptanceTest {
                             "MARIADB_DATABASE",
                             "PGSQL_INSTANCE",
                             "PGSQL_USER",
-                            "PGSQL_DATABASE"
+                            "PGSQL_DATABASE",
+                            "IPV4_NUMBER",
+                            "IPV6_NUMBER"
                         ]
                         """));
         // @formatter:on

src/test/java/net/hostsharing/hsadminng/hs/hosting/asset/HsHostingAssetTypeUnitTest.java

@@ -14,6 +14,49 @@ class HsHostingAssetTypeUnitTest {
                 ## HostingAsset Type Structure
 
 
+                ### Webspace+Server
+                
+                ```plantuml
+                @startuml
+                left to right direction
+                
+                package Booking #feb28c {
+                    entity BI_PRIVATE_CLOUD
+                    entity BI_CLOUD_SERVER
+                    entity BI_MANAGED_SERVER
+                    entity BI_MANAGED_WEBSPACE
+                }
+                
+                package Hosting #feb28c{
+                    package Server #99bcdb {
+                        entity HA_CLOUD_SERVER
+                        entity HA_MANAGED_SERVER
+                        entity HA_IPV4_NUMBER
+                        entity HA_IPV6_NUMBER
+                    }
+                
+                }
+                
+                BI_CLOUD_SERVER *--> BI_PRIVATE_CLOUD
+                BI_MANAGED_SERVER *--> BI_PRIVATE_CLOUD
+                BI_MANAGED_WEBSPACE *--> BI_MANAGED_SERVER
+                
+                HA_CLOUD_SERVER *==> BI_CLOUD_SERVER
+                HA_MANAGED_SERVER *==> BI_MANAGED_SERVER
+                HA_IPV4_NUMBER o..> HA_CLOUD_SERVER
+                HA_IPV4_NUMBER o..> HA_MANAGED_SERVER
+                HA_IPV6_NUMBER o..> HA_CLOUD_SERVER
+                HA_IPV6_NUMBER o..> HA_MANAGED_SERVER
+                
+                package Legend #white {
+                    SUB_ENTITY1 *--> REQUIRED_PARENT_ENTITY
+                    SUB_ENTITY2 *..> OPTIONAL_PARENT_ENTITY
+                    ASSIGNED_ENTITY1 o--> REQUIRED_ASSIGNED_TO_ENTITY1
+                    ASSIGNED_ENTITY2 o..> OPTIONAL_ASSIGNED_TO_ENTITY2
+                }
+                Booking -down[hidden]->Legend
+                ```
+                
                 ### Domain
                 
                 ```plantuml
@@ -37,12 +80,6 @@ class HsHostingAssetTypeUnitTest {
                         entity HA_EMAIL_ADDRESS
                     }
                 
-                    package Server #99bcdb {
-                        entity HA_CLOUD_SERVER
-                        entity HA_MANAGED_SERVER
-                        entity HA_IP_NUMBER
-                    }
-
                     package Webspace #99bcdb {
                         entity HA_MANAGED_WEBSPACE
                         entity HA_UNIX_USER
@@ -55,25 +92,19 @@ class HsHostingAssetTypeUnitTest {
                 BI_MANAGED_SERVER *--> BI_PRIVATE_CLOUD
                 BI_MANAGED_WEBSPACE *--> BI_MANAGED_SERVER
                 
-                HA_CLOUD_SERVER *==> BI_CLOUD_SERVER
-                HA_MANAGED_SERVER *==> BI_MANAGED_SERVER
                 HA_MANAGED_WEBSPACE *==> BI_MANAGED_WEBSPACE
-                HA_MANAGED_WEBSPACE o..> HA_MANAGED_SERVER
                 HA_UNIX_USER *==> HA_MANAGED_WEBSPACE
                 HA_EMAIL_ALIAS *==> HA_MANAGED_WEBSPACE
                 HA_DOMAIN_SETUP o..> HA_DOMAIN_SETUP
                 HA_DOMAIN_DNS_SETUP *==> HA_DOMAIN_SETUP
-                HA_DOMAIN_DNS_SETUP o..> HA_MANAGED_WEBSPACE
+                HA_DOMAIN_DNS_SETUP o--> HA_MANAGED_WEBSPACE
                 HA_DOMAIN_HTTP_SETUP *==> HA_DOMAIN_SETUP
-                HA_DOMAIN_HTTP_SETUP o..> HA_UNIX_USER
+                HA_DOMAIN_HTTP_SETUP o--> HA_UNIX_USER
                 HA_DOMAIN_SMTP_SETUP *==> HA_DOMAIN_SETUP
-                HA_DOMAIN_SMTP_SETUP o..> HA_MANAGED_WEBSPACE
+                HA_DOMAIN_SMTP_SETUP o--> HA_MANAGED_WEBSPACE
                 HA_DOMAIN_MBOX_SETUP *==> HA_DOMAIN_SETUP
-                HA_DOMAIN_MBOX_SETUP o..> HA_MANAGED_WEBSPACE
+                HA_DOMAIN_MBOX_SETUP o--> HA_MANAGED_WEBSPACE
                 HA_EMAIL_ADDRESS *==> HA_DOMAIN_MBOX_SETUP
-                HA_IP_NUMBER o..> HA_CLOUD_SERVER
-                HA_IP_NUMBER o..> HA_MANAGED_SERVER
-                HA_IP_NUMBER o..> HA_MANAGED_WEBSPACE
                 
                 package Legend #white {
                     SUB_ENTITY1 *--> REQUIRED_PARENT_ENTITY
@@ -104,12 +135,6 @@ class HsHostingAssetTypeUnitTest {
                         entity HA_MARIADB_DATABASE
                     }
                 
-                    package Server #99bcdb {
-                        entity HA_CLOUD_SERVER
-                        entity HA_MANAGED_SERVER
-                        entity HA_IP_NUMBER
-                    }
-
                     package Webspace #99bcdb {
                         entity HA_MANAGED_WEBSPACE
                         entity HA_UNIX_USER
@@ -122,19 +147,12 @@ class HsHostingAssetTypeUnitTest {
                 BI_MANAGED_SERVER *--> BI_PRIVATE_CLOUD
                 BI_MANAGED_WEBSPACE *--> BI_MANAGED_SERVER
                 
-                HA_CLOUD_SERVER *==> BI_CLOUD_SERVER
-                HA_MANAGED_SERVER *==> BI_MANAGED_SERVER
                 HA_MANAGED_WEBSPACE *==> BI_MANAGED_WEBSPACE
-                HA_MANAGED_WEBSPACE o..> HA_MANAGED_SERVER
                 HA_UNIX_USER *==> HA_MANAGED_WEBSPACE
                 HA_EMAIL_ALIAS *==> HA_MANAGED_WEBSPACE
-                HA_MARIADB_INSTANCE *==> HA_MANAGED_SERVER
                 HA_MARIADB_USER *==> HA_MANAGED_WEBSPACE
-                HA_MARIADB_USER o..> HA_MARIADB_INSTANCE
+                HA_MARIADB_USER o--> HA_MARIADB_INSTANCE
                 HA_MARIADB_DATABASE *==> HA_MARIADB_USER
-                HA_IP_NUMBER o..> HA_CLOUD_SERVER
-                HA_IP_NUMBER o..> HA_MANAGED_SERVER
-                HA_IP_NUMBER o..> HA_MANAGED_WEBSPACE
                 
                 package Legend #white {
                     SUB_ENTITY1 *--> REQUIRED_PARENT_ENTITY
@@ -165,12 +183,6 @@ class HsHostingAssetTypeUnitTest {
                         entity HA_PGSQL_DATABASE
                     }
                 
-                    package Server #99bcdb {
-                        entity HA_CLOUD_SERVER
-                        entity HA_MANAGED_SERVER
-                        entity HA_IP_NUMBER
-                    }
-
                     package Webspace #99bcdb {
                         entity HA_MANAGED_WEBSPACE
                         entity HA_UNIX_USER
@@ -183,19 +195,12 @@ class HsHostingAssetTypeUnitTest {
                 BI_MANAGED_SERVER *--> BI_PRIVATE_CLOUD
                 BI_MANAGED_WEBSPACE *--> BI_MANAGED_SERVER
                 
-                HA_CLOUD_SERVER *==> BI_CLOUD_SERVER
-                HA_MANAGED_SERVER *==> BI_MANAGED_SERVER
                 HA_MANAGED_WEBSPACE *==> BI_MANAGED_WEBSPACE
-                HA_MANAGED_WEBSPACE o..> HA_MANAGED_SERVER
                 HA_UNIX_USER *==> HA_MANAGED_WEBSPACE
                 HA_EMAIL_ALIAS *==> HA_MANAGED_WEBSPACE
-                HA_PGSQL_INSTANCE *==> HA_MANAGED_SERVER
                 HA_PGSQL_USER *==> HA_MANAGED_WEBSPACE
-                HA_PGSQL_USER o..> HA_PGSQL_INSTANCE
+                HA_PGSQL_USER o--> HA_PGSQL_INSTANCE
                 HA_PGSQL_DATABASE *==> HA_PGSQL_USER
-                HA_IP_NUMBER o..> HA_CLOUD_SERVER
-                HA_IP_NUMBER o..> HA_MANAGED_SERVER
-                HA_IP_NUMBER o..> HA_MANAGED_WEBSPACE
                 
                 package Legend #white {
                     SUB_ENTITY1 *--> REQUIRED_PARENT_ENTITY

src/test/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HostingAssetEntityValidatorRegistryUnitTest.java

@@ -45,7 +45,9 @@ class HostingAssetEntityValidatorRegistryUnitTest {
                 HsHostingAssetType.MARIADB_DATABASE,
                 HsHostingAssetType.PGSQL_INSTANCE,
                 HsHostingAssetType.PGSQL_USER,
-                HsHostingAssetType.PGSQL_DATABASE
+                HsHostingAssetType.PGSQL_DATABASE,
+                HsHostingAssetType.IPV4_NUMBER,
+                HsHostingAssetType.IPV6_NUMBER
         );
     }
 }

src/test/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HsIPv4NumberHostingAssetValidatorUnitTest.java

@@ -0,0 +1,120 @@
+package net.hostsharing.hsadminng.hs.hosting.asset.validators;
+
+import net.hostsharing.hsadminng.hs.booking.item.HsBookingItemEntity;
+import net.hostsharing.hsadminng.hs.booking.item.HsBookingItemType;
+import net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetEntity;
+import net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetEntity.HsHostingAssetEntityBuilder;
+import net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.EnumSource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import java.util.Map;
+
+import static java.util.Map.entry;
+import static net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType.IPV4_NUMBER;
+import static net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType.MANAGED_WEBSPACE;
+import static net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType.UNIX_USER;
+import static org.assertj.core.api.Assertions.assertThat;
+
+class HsIPv4NumberHostingAssetValidatorUnitTest {
+
+    static HsHostingAssetEntityBuilder validEntityBuilder() {
+        return HsHostingAssetEntity.builder()
+                .type(IPV4_NUMBER)
+                .identifier("83.223.95.145");
+    }
+
+    @Test
+    void containsExpectedProperties() {
+        // when
+        final var validator = HostingAssetEntityValidatorRegistry.forType(IPV4_NUMBER);
+
+        // then
+        assertThat(validator.properties()).map(Map::toString).isEmpty();
+    }
+
+    @Test
+    void acceptsValidEntity() {
+        // given
+        final var givenEntity = validEntityBuilder().build();
+        final var validator = HostingAssetEntityValidatorRegistry.forType(givenEntity.getType());
+
+        // when
+        final var result = validator.validateEntity(givenEntity);
+
+        // then
+        assertThat(result).isEmpty();
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"a.b.c.d", "83.223.95", "83.223.95.145.1", "2a01:37:1000::53df:5f91:0"})
+    void rejectsInvalidIdentifier(final String givenIdentifier) {
+        // given
+        final var givenEntity = validEntityBuilder().identifier(givenIdentifier).build();
+        final var validator = HostingAssetEntityValidatorRegistry.forType(givenEntity.getType());
+
+        // when
+        final var result = validator.validateEntity(givenEntity);
+
+        // then
+        assertThat(result).containsExactly(
+                "'identifier' expected to match '^((25[0-5]|(2[0-4]|1\\d|[1-9]|)\\d)\\.?\\b){4}$', but is '" + givenIdentifier + "'"
+        );
+    }
+
+    @ParameterizedTest
+    @EnumSource(value = HsHostingAssetType.class, names = { "CLOUD_SERVER", "MANAGED_SERVER", "MANAGED_WEBSPACE" })
+    void acceptsValidReferencedEntity(final HsHostingAssetType givenAssignedToAssetType) {
+        // given
+        final var ipNumberHostingAssetEntity = validEntityBuilder()
+                .assignedToAsset(HsHostingAssetEntity.builder().type(givenAssignedToAssetType).build())
+                .build();
+        final var validator = HostingAssetEntityValidatorRegistry.forType(ipNumberHostingAssetEntity.getType());
+
+        // when
+        final var result = validator.validateEntity(ipNumberHostingAssetEntity);
+
+        // then
+        assertThat(result).isEmpty();
+    }
+
+    @Test
+    void rejectsInvalidReferencedEntities() {
+        // given
+        final var ipNumberHostingAssetEntity = validEntityBuilder()
+                .bookingItem(HsBookingItemEntity.builder().type(HsBookingItemType.CLOUD_SERVER).build())
+                .parentAsset(HsHostingAssetEntity.builder().type(MANAGED_WEBSPACE).build())
+                .assignedToAsset(HsHostingAssetEntity.builder().type(UNIX_USER).build())
+                .build();
+        final var validator = HostingAssetEntityValidatorRegistry.forType(ipNumberHostingAssetEntity.getType());
+
+        // when
+        final var result = validator.validateEntity(ipNumberHostingAssetEntity);
+
+        // then
+        assertThat(result).containsExactlyInAnyOrder(
+                "'IPV4_NUMBER:83.223.95.145.bookingItem' must be null but is of type CLOUD_SERVER",
+                "'IPV4_NUMBER:83.223.95.145.parentAsset' must be null but is of type MANAGED_WEBSPACE",
+                "'IPV4_NUMBER:83.223.95.145.assignedToAsset' must be null or of type CLOUD_SERVER or MANAGED_SERVER or MANAGED_WEBSPACE but is of type UNIX_USER");
+    }
+
+    @Test
+    void rejectsInvalidProperties() {
+        // given
+        final var ipNumberHostingAssetEntity = validEntityBuilder()
+                .config(Map.ofEntries(
+                        entry("any", "false")
+                ))
+                .build();
+        final var validator = HostingAssetEntityValidatorRegistry.forType(ipNumberHostingAssetEntity.getType());
+
+        // when
+        final var result = validator.validateEntity(ipNumberHostingAssetEntity);
+
+        // then
+        assertThat(result).containsExactlyInAnyOrder(
+                "'IPV4_NUMBER:83.223.95.145.config.any' is not expected but is set to 'false'");
+    }
+}

src/test/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HsIPv6NumberHostingAssetValidatorUnitTest.java

@@ -0,0 +1,120 @@
+package net.hostsharing.hsadminng.hs.hosting.asset.validators;
+
+import net.hostsharing.hsadminng.hs.booking.item.HsBookingItemEntity;
+import net.hostsharing.hsadminng.hs.booking.item.HsBookingItemType;
+import net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetEntity;
+import net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetEntity.HsHostingAssetEntityBuilder;
+import net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.EnumSource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import java.util.Map;
+
+import static java.util.Map.entry;
+import static net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType.IPV6_NUMBER;
+import static net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType.MANAGED_WEBSPACE;
+import static net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType.UNIX_USER;
+import static org.assertj.core.api.Assertions.assertThat;
+
+class HsIPv6NumberHostingAssetValidatorUnitTest {
+
+    static HsHostingAssetEntityBuilder validEntityBuilder() {
+        return HsHostingAssetEntity.builder()
+                .type(IPV6_NUMBER)
+                .identifier("2001:db8:3333:4444:5555:6666:7777:8888");
+    }
+
+    @Test
+    void containsExpectedProperties() {
+        // when
+        final var validator = HostingAssetEntityValidatorRegistry.forType(IPV6_NUMBER);
+
+        // then
+        assertThat(validator.properties()).map(Map::toString).isEmpty();
+    }
+
+    @Test
+    void acceptsValidEntity() {
+        // given
+        final var givenEntity = validEntityBuilder().build();
+        final var validator = HostingAssetEntityValidatorRegistry.forType(givenEntity.getType());
+
+        // when
+        final var result = validator.validateEntity(givenEntity);
+
+        // then
+        assertThat(result).isEmpty();
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"83.223.95", "2a01:37:1000::53df:5f91:0:123::123"})
+    void rejectsInvalidIdentifier(final String givenIdentifier) {
+        // given
+        final var givenEntity = validEntityBuilder().identifier(givenIdentifier).build();
+        final var validator = HostingAssetEntityValidatorRegistry.forType(givenEntity.getType());
+
+        // when
+        final var result = validator.validateEntity(givenEntity);
+
+        // then
+        assertThat(result).contains(
+                "'identifier' expected to be a valid IPv6 address, but is '" + givenIdentifier + "'"
+        );
+    }
+
+    @ParameterizedTest
+    @EnumSource(value = HsHostingAssetType.class, names = { "CLOUD_SERVER", "MANAGED_SERVER", "MANAGED_WEBSPACE" })
+    void acceptsValidReferencedEntity(final HsHostingAssetType givenAssignedToAssetType) {
+        // given
+        final var ipNumberHostingAssetEntity = validEntityBuilder()
+                .assignedToAsset(HsHostingAssetEntity.builder().type(givenAssignedToAssetType).build())
+                .build();
+        final var validator = HostingAssetEntityValidatorRegistry.forType(ipNumberHostingAssetEntity.getType());
+
+        // when
+        final var result = validator.validateEntity(ipNumberHostingAssetEntity);
+
+        // then
+        assertThat(result).isEmpty();
+    }
+
+    @Test
+    void rejectsInvalidReferencedEntities() {
+        // given
+        final var ipNumberHostingAssetEntity = validEntityBuilder()
+                .bookingItem(HsBookingItemEntity.builder().type(HsBookingItemType.CLOUD_SERVER).build())
+                .parentAsset(HsHostingAssetEntity.builder().type(MANAGED_WEBSPACE).build())
+                .assignedToAsset(HsHostingAssetEntity.builder().type(UNIX_USER).build())
+                .build();
+        final var validator = HostingAssetEntityValidatorRegistry.forType(ipNumberHostingAssetEntity.getType());
+
+        // when
+        final var result = validator.validateEntity(ipNumberHostingAssetEntity);
+
+        // then
+        assertThat(result).containsExactlyInAnyOrder(
+                "'IPV6_NUMBER:2001:db8:3333:4444:5555:6666:7777:8888.bookingItem' must be null but is of type CLOUD_SERVER",
+                "'IPV6_NUMBER:2001:db8:3333:4444:5555:6666:7777:8888.parentAsset' must be null but is of type MANAGED_WEBSPACE",
+                "'IPV6_NUMBER:2001:db8:3333:4444:5555:6666:7777:8888.assignedToAsset' must be null or of type CLOUD_SERVER or MANAGED_SERVER or MANAGED_WEBSPACE but is of type UNIX_USER");
+    }
+
+    @Test
+    void rejectsInvalidProperties() {
+        // given
+        final var ipNumberHostingAssetEntity = validEntityBuilder()
+                .config(Map.ofEntries(
+                        entry("any", "false")
+                ))
+                .build();
+        final var validator = HostingAssetEntityValidatorRegistry.forType(ipNumberHostingAssetEntity.getType());
+
+        // when
+        final var result = validator.validateEntity(ipNumberHostingAssetEntity);
+
+        // then
+        assertThat(result).containsExactlyInAnyOrder(
+                "'IPV6_NUMBER:2001:db8:3333:4444:5555:6666:7777:8888.config.any' is not expected but is set to 'false'");
+    }
+}

src/test/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HsPostgreSqlDatabaseHostingAssetValidatorUnitTest.java

@@ -31,7 +31,7 @@ class HsPostgreSqlDatabaseHostingAssetValidatorUnitTest {
             .type(PGSQL_USER)
             .parentAsset(TEST_MANAGED_WEBSPACE_HOSTING_ASSET)
             .assignedToAsset(GIVEN_PGSQL_INSTANCE)
-            .identifier("xyz00_temp")
+            .identifier("xyz00_user")
             .caption("some valid test PgSql-User")
             .config(new HashMap<>(ofEntries(
                     entry("password", "Hallo Datenbank, lass mich rein!")
@@ -42,7 +42,7 @@ class HsPostgreSqlDatabaseHostingAssetValidatorUnitTest {
         return HsHostingAssetEntity.builder()
                 .type(PGSQL_DATABASE)
                 .parentAsset(GIVEN_PGSQL_USER)
-                .identifier("xyz00_temp")
+                .identifier("xyz00_db")
                 .caption("some valid test PgSql-Database")
                 .config(new HashMap<>(ofEntries(
                         entry("encoding", "LATIN1")
@@ -94,8 +94,9 @@ class HsPostgreSqlDatabaseHostingAssetValidatorUnitTest {
 
         // then
         assertThat(result).containsExactlyInAnyOrder(
-                "'PGSQL_DATABASE:xyz00_temp.config.unknown' is not expected but is set to 'wrong'",
+                "'PGSQL_DATABASE:xyz00_db.bookingItem' must be null but is of type CLOUD_SERVER",
-                "'PGSQL_DATABASE:xyz00_temp.config.encoding' is expected to be of type String, but is of type Integer"
+                "'PGSQL_DATABASE:xyz00_db.parentAsset' must be of type PGSQL_USER but is of type PGSQL_INSTANCE",
+                "'PGSQL_DATABASE:xyz00_db.assignedToAsset' must be null but is of type PGSQL_INSTANCE"
         );
     }
 
@@ -115,8 +116,8 @@ class HsPostgreSqlDatabaseHostingAssetValidatorUnitTest {
 
         // then
         assertThat(result).containsExactlyInAnyOrder(
-                "'PGSQL_DATABASE:xyz00_temp.config.unknown' is not expected but is set to 'wrong'",
+                "'PGSQL_DATABASE:xyz00_db.config.unknown' is not expected but is set to 'wrong'",
-                "'PGSQL_DATABASE:xyz00_temp.config.encoding' is expected to be of type String, but is of type Integer"
+                "'PGSQL_DATABASE:xyz00_db.config.encoding' is expected to be of type String, but is of type Integer"
         );
     }