Company XYZ has been getting numerous complaints that one of their employees has been actively probing remote DNS servers and attempting to extract information from them. After investigation it was…

Company XYZ has been getting numerous complaints that one of their employees has been actively probing remote DNS servers and attempting to extract information from them. After investigation it was detected that Jack had used the nslookup command extensively and he also issued commands within nslookup such as sever [remoteip] where [remoteip] is the IP address of the target he was probing. Further investigation also revealed that he used the command ls d targetdomain.com where targetdomain.com was the domain name he was attempting to get more info about; what was Jack really attempting to achieve in this case?