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##### SUMMARY
The `win_dns_client` module always shows "changed" when setting the adapter to use DHCP because the PowerShell cmdlets and WMI classes don't have a reliable way to determine that DHCP assigned nameservers are already in use.

A comment in the module suggests checking the registry.

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
win_dns_client

##### ADDITIONAL INFORMATION
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As is, it's not possible to know whether a change was actually made (or would be made in check mode).
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ANSIBLE_METADATA = {'metadata_version': '1.1',
                    'status': ['preview'],
                    'supported_by': 'core'}
DOCUMENTATION = r'''
---
module: win_dns_client
version_added: "2.3"
short_description: Configures DNS lookup on Windows hosts
description:
  - The C(win_dns_client) module configures the DNS client on Windows network adapters.
options:
  adapter_names:
    description:
      - Adapter name or list of adapter names for which to manage DNS settings ('*' is supported as a wildcard value).
      - The adapter name used is the connection caption in the Network Control Panel or the InterfaceAlias of C(Get-DnsClientServerAddress).
    type: list
    required: yes
  dns_servers:
    description:
      - Single or ordered list of DNS servers (IPv4 and IPv6 addresses) to configure for lookup. An empty list will configure the adapter to use the
        DHCP-assigned values on connections where DHCP is enabled, or disable DNS lookup on statically-configured connections.
      - IPv6 DNS servers can only be set on Windows Server 2012 or newer, older hosts can only set IPv4 addresses.
      - Before 2.10 use ipv4_addresses instead.
    type: list
    required: yes
    aliases: [ "ipv4_addresses", "ip_addresses", "addresses" ]
notes:
  - When setting an empty list of DNS server addresses on an adapter with DHCP enabled, a change will always be registered, since it is not possible to