I remember reading about the no-www
movement years ago. At that time it struck me as a cool thing to do, but I now know
that no-www is a really bad idea in general. That’s because the DNS system lets you
assign CNAME records
to subdomains, including the
www subdomain, but only A or AAAA records to root domains.
In other words, you can say that
www.example.com is the same as
test.example.org, but you
can only say that
example.com is the same as a particular IP address.
What’s the benefit of this? Well, if you use a CNAME you can let the owner of
test.example.org deal with anycast and routing issues, but if you use A
records you have to deal with them yourself. If you do decide to deal with
them yourself, you’ll be frustrated when your DNS updates take a while
More generally, CNAME is an example of the most powerful law of computer science in action, and A isn’t.
All problems in computer science can be solved by another level of indirection. David Wheeler
See Heroku’s documentation on the matter.