I'm trying to find any form of documentation available to (in)validate a behavior on the Internet that involves DNS and lazy, web browsing users. It is not uncommon for DNS administrators to put something akin to the following in their zone files for a particular domain (assume best practices followed for SOA including proper $ORIGIN statements, etc):
IN A 184.108.40.206 www IN A 220.127.116.11
This has the effect of allowing somebody to type "http://black-panther.us/" into their web browser and get to my web page because an A RR (18.104.22.168) is returned that would be the same as if they typed in "http://www.black-panther.us/". As I said above, this is primarily done to allow lazy web browsers such as myself to type only the domain in the URL bar and get taken to the website. I could go so far as to say that this is now expected behavior on the public Internet. However, just because something is expected doesn't mean it's correct (the opposite is far too often the case, where broken behavior has come to be expected or even accepted as correct). Hence, I ask you, the all-knowing web: where is this behavior documented as being acceptable in the relevant RFCs or DNS best practices papers? So far I have reviewed a slew of RFCs, including 1912, 2181, and 1033, and I have yet to see this described as something that is actually approved and correct. RFC 2219 somewhat references the behavior I'm describing in the second paragraph of section 1 ("Rationale"), but is using it to outline a case for the remainder of the RFC. I've found no allusion to this in the "Best Practices" documentation I've scanned during my scrounging, either.
So is this just a common practice by lazy administrators like myself to keep lazy users like myself from kvetching, or is this actually documented somewhere as being appropriate?
I find it both amusing and, simultaneously, frustrating that I can tell you which RFC indicates an underscore cannot be used in a name (RFC 952) but I'm drawing a complete blank on this.