What does Windows error code 9978 (DNS_ERROR_SUBNET_DOES_NOT_EXIST) mean?

DNS_ERROR_SUBNET_DOES_NOT_EXIST

DNS_ERROR_SUBNET_DOES_NOT_EXIST means the operation refers to an IPv4 or IPv6 prefix that is not part of the named DNS client-subnet definition.

What to check for DNS_ERROR_SUBNET_DOES_NOT_EXIST

• Inspect the exact address and prefix length; a host address and a network prefix are not interchangeable.
• Check whether the prefix belongs to a different client-subnet name.
• When modifying a definition, preserve any existing prefixes that are still needed by policy matching.

Get-DnsServerClientSubnet

Microsoft: Get-DnsServerClientSubnet

Microsoft: Set-DnsServerClientSubnet

Microsoft: Add-DnsServerClientSubnet

Where the result is returned

This result is Win32 system error 9978 (0x000026FA) from winerror.h. AllStat describes it as “The IP subnet specified does not exist in the client subnet.”