Wayne, who has a twisted mind, has been watching security mailing lists very closely. Today he has seen a new vulnerability announcement that affects multiple mail servers. Jack wishes to scan the…

Wayne, who has a twisted mind, has been watching security mailing lists very closely. Today he has seen a new vulnerability announcement that affects multiple mail servers. Jack wishes to scan the internet for servers that are running one of those vulnerable mail servers. His intent is to do this passively at first by doing DNS queries using the nslookup command. What type of resource record is Wayne looking for within the DNS query results?