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+Cidr
+==
+
+Validates that a value is a valid CIDR notation. By default, this will validate
+the CIDR's IP and netmask both for version 4 and version 6, with the option of allowing
+only one type of IP version to be valid. It also supports a minimum and maximum range
+constraint in which the value of the netmask is valid.
+
+==========  ===================================================================
+Applies to  :ref:`property or method <validation-property-target>`
+Options     - `groups`_
+            - `message`_
+            - `netmaskRangeViolationMessage`_
+            - `payload`_
+            - `version`_
+Class       :class:`Symfony\\Component\\Validator\\Constraints\\Cidr`
+Validator   :class:`Symfony\\Component\\Validator\\Constraints\\CidrValidator`
+==========  ===================================================================
+
+Basic Usage
+-----------
+
+.. configuration-block::
+
+    .. code-block:: php-annotations
+
+        // src/Entity/Author.php
+        namespace App\Entity;
+
+        use Symfony\Component\Validator\Constraints as Assert;
+
+        class Author
+        {
+            /**
+             * @Assert\Cidr
+             */
+            protected $cidrNotation;
+        }
+
+    .. code-block:: php-attributes
+
+        // src/Entity/Author.php
+        namespace App\Entity;
+
+        use Symfony\Component\Validator\Constraints as Assert;
+
+        class Author
+        {
+            #[Assert\Cidr]
+            protected $cidrNotation;
+        }
+
+    .. code-block:: yaml
+
+        # config/validator/validation.yaml
+        App\Entity\Author:
+            properties:
+                cidrNotation:
+                    - Cidr: ~
+
+    .. code-block:: xml
+
+        <!-- config/validator/validation.xml -->
+        <?xml version="1.0" encoding="UTF-8" ?>
+        <constraint-mapping xmlns="http://symfony.com/schema/dic/constraint-mapping"
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+            xsi:schemaLocation="http://symfony.com/schema/dic/constraint-mapping https://symfony.com/schema/dic/constraint-mapping/constraint-mapping-1.0.xsd">
+
+            <class name="App\Entity\Author">
+                <property name="cidrNotation">
+                    <constraint name="Cidr"/>
+                </property>
+            </class>
+        </constraint-mapping>
+
+    .. code-block:: php
+
+        // src/Entity/Author.php
+        namespace App\Entity;
+
+        use Symfony\Component\Validator\Constraints as Assert;
+        use Symfony\Component\Validator\Mapping\ClassMetadata;
+
+        class Author
+        {
+            public static function loadValidatorMetadata(ClassMetadata $metadata)
+            {
+                $metadata->addPropertyConstraint('cidrNotation', new Assert\Cidr());
+            }
+        }
+
+.. include:: /reference/constraints/_empty-values-are-valid.rst.inc
+
+Options
+-------
+
+.. include:: /reference/constraints/_groups-option.rst.inc
+
+``message``
+~~~~~~~~~~~
+
+**type**: ``string`` **default**: ``This value is not a valid CIDR notation.``
+
+This message is shown if the string is not a valid CIDR notation.
+
+``netmaskMin``
+~~~~~~~~~~~
+
+**type**: ``integer`` **default**: ``0``
+
+It's a constraint for the lowest value a valid netmask may have.
+
+``netmaskMax``
+~~~~~~~~~~~
+
+**type**: ``string`` **default**: ``32 for IPv4 or 128 for IPv6``
+
+It's a constraint for the biggest value a valid netmask may have.
+
+``netmaskRangeViolationMessage``
+~~~~~~~~~~~
+
+**type**: ``string`` **default**: ``The value of the netmask should be between {{ min }} and {{ max }}.``
+
+This message is shown if the value of the CIDR's netmask is bigger then the value of the `max_` or lower than
+the value of the `min_`.
+
+You can use the following parameters in this message:
+
+===============  ==============================================================
+Parameter        Description
+===============  ==============================================================
+``{{ min }}``  The minimum value a CIDR netmask may have
+``{{ max }}``  The maximum value a CIDR netmask may have
+===============  ==============================================================
+
+.. include:: /reference/constraints/_payload-option.rst.inc
+
+``version``
+~~~~~~~~~~~
+
+**type**: ``string`` **default**: ``all``
+
+This determines exactly *how* the CIDR notation is validated and can take one
+of a variety of different values:
+
+**All ranges**
+
+``4``
+    Validates for CIDR notations that have an IPv4.
+``6``
+    Validates for CIDR notations that have an IPv6.
+``all``
+    Validates all CIDR formats
+