De acordo com o link e um teste rápido usando apenas ipconfig /displaydns
da linha de comando, ele não mantém nenhuma informação de data ou hora nas entradas para que você modifique a consulta do Powerhhell para trazer resultados de backup.
/displaydns | The command to display a client resolver cache.
The ipconfig /displaydns command provides you with a means to view the contents of the DNS client resolver cache, which includes entries preloaded from the local Hosts file, as well as any recently obtained resource records for name queries resolved by the system. This information is used by the DNS Client service to quickly resolve frequently queried names before it queries its configured DNS servers.