A possibly needless clarification: The DNS is organised by class, name, and then type. Each class is a seperate space, so ycombinator.com in the IN (Internet) class and ycombinator.com in any other class aren't necessarily the same entities. Types can also be class specific, for example A in the IN class is different to A in the CHAOS class. Types may also only be defined in specific classes like SRV (amongst others) in IN. (Aside: this model is why CNAMEs can't coexist with other records.)