Yesterday, I noticed that a client (who has just enough knowledge of networking to be dangerous) had messed up one of his nameserver records. We'd recently relocated to a different colocation provider, and ns2.his-domain.com was pointing back to the network in the recently vacated cabinet. I instructed him, "go to your registrar, and change the IP this name server points to, because until then you have only one working nameserver for all your clients' domains".
Due to time zone differences - he lives in Europe, and I'm in the US - we couldn't talk live.
This morning, I discovered that he'd used a shotgun to solve this problem. Not only did he change ns2.his-domain.com to point to the correct IP, he then proceeded to create more host records - at the registrar level, using their web tools for creating name servers - for every host name he'd ever used in the past, and some that he thought he might want in the future, all of them pointing to the same IP.
ns3.his-domain.com, ns4.his-domain.com, www.his-domain.com, ftp.his-domain.com, kirk.his-domain.com, spock.his-domain.com, scotty.his-domain.com, etc. - all of these may now be looked up with Whois, bypassing our local name server, cluttering up the root name space. He created about twenty host records in the domain registry, all of them pointing to the exact same IP.
My gut feeling is that this is very, very bad. It defeats the fundamental design of DNS, which is supposed to be hierarchical!
What are the consequences of this? Is there anything in the standards - in RFCs or elsewhere - that prohibits this, and describes what might happen as a result?
Example (name changed to protect the guilty:)
$ whois spock.his-domain.com Whois Server Version 2.0 Server Name: SPOCK.HIS-DOMAIN.COM IP Address: 18.104.22.168 Registrar: COMPUTER SERVICES LANGENBACH GMBH DBA JOKER.COM Whois Server: whois.joker.com Referral URL: http://www.joker.com