From Paterva Wiki
This transform attempts to find DNSName on the specified Domain. This is done by testing a list of DNS Names and seeing if they exists. The list of names that are tested for can be configured inside the transform. The default list contains the following names: www,mail,mx,ns,ftp,webmail,web,gateway,secure,intranet,extranet,smtp,pop The specified domain is appended to the name and tested. If it exists it is returned as a DNS Name.
Used to find DNS names at a specific domain
Domain via transform DomainToDNSName_DNSBrute to