This article archives a conversation, which took place in a subreddit post (original source linked below) and to which I contributed a solution or answer (with the u/MasterofSynapse handle), in a Q&A format.
Original Reddit post: https://www.reddit.com/r/CloudFlare/comments/10adbml/most_efficient_dns_spec_help_please/
Given these names:
my.example.com one.my.example.com two.my.example.com three.my.example.com
I want all of these to point to the same IP.
I can make it work with two DNS entries:
But is there a way to achieve this with only a single DNS entry?
No, there isn't, since my.example.com and *.my.example.com are different "levels" of example.com, my. being a Third-Level-Domain, while *. is a Fourth-Level-Domain.
So to provide both my. and *.my. you need both records.