nslookup root
Changes the default server to the server for the root of the Domain Name System (DNS) domain name space. Windows commands reference
On Windows
Windows
Changes the default server to the server for the root of the Domain Name System (DNS) domain name space. Currently, the ns.nic.ddn.mil name server is used. You can change the name of the root server using the nslookup set root command. NOTE: This command is the same as lserver ns.nic.ddn.mil.
root
/?Displays help at the command prompt./helpDisplays help at the command prompt.