KLH@SRI-NIC.ARPA (Ken Harrenstien) (10/23/85)
Several people have expressed confusion about the NIC's policy for registering host nicknames, and have somehow been led to believe that the NIC has something against second or third-level domain names. This message is an attempt to clarify our position and explain where the issue started. As far as the NIC host table is concerned, there is no distinction between a domain style name and and "old" host name; they are both just names. The level, or number of domains in a name, is completely irrelevant. The first name in a host entry is the official name which must be used in any external references to that host. All other names are considered "nicknames". In order to reduce the size of the host table, we strongly discourage nicknames. In general, the only valid reason for a nickname to exist is the fact that the nickname once was, or may become, the official name for that host. When official names change, some period of overlapping existence is needed to allow time for the change to propagate to all hosts; not every site updates their copy of the host table every night. Thus, a more accurate term for NIC "nicknames" would be "alternate names", since these are only intended to keep things working, rather than to allow everyone to use their favorite hosts on a first-name basis. Nicknames intended for the latter purpose are best handled locally. There are still many old, short "first-name" nicknames which remain for various historical reasons. The advent of the domain name system, with the mandatory change-over to domain-style names, is a great opportunity to start getting rid of them. Meanwhile, we try to make sure that any new entries have no nicknames whenever possible. One of the philosophical goals we were aiming for while working out the structure of the domain name system was to end up with only ONE name for any particular host, even though this site might exist on different networks. By using neutral top-level domains of COM, EDU, and the like, we hoped to avoid a multiplicity of names resulting from political claim staking (MC.MIT.ARPA = MC.MIT.CHAOS = MC.MIT.CSNET = MC.MIT.DOE = etc etc) and to encourage the selection of just one name which could then be used by all (or most) organizations and networks using a particular host. This is the underlying basis for the "no domain nicknames" policy; it is not a technical problem, but rather a philosophy which we think will make life easier in the long run (and having maintained these lists for years, we do speak from experience). What is now causing confusion is the fact that many people have used the NIC host table as a way of vectoring their mail to different places at different times, by shuffling nicknames around. This is not really how the table was meant to be used, and the creation of MF type records in the domain name system is a reflection of the fact that mail addressing is not the same as TELNET or FTP host addressing. In the particular case that started all this, Bruce Nemnich wanted to register GODOT.THINK.COM as an official name, with THINK.COM as a nickname. The intent here was to have every machine in the THINK.COM domain fake up their return-path and sender-address to xyz@THINK.COM which would then relay responses to the appropriate place. Now, there is no inherent technical problem with simply sticking those names in our database. However, this request was initially rejected, on the basis of our simple "no domain nickname" guideline, by the staff members who serve as HOSTMASTER. When later they anxiously asked me for confirmation, I allowed as how "we could do it-- but it would be wrong." Remember, mailers are still required to use official host names in anything which goes out. Supposing that we carried out the THINK.COM request, the THINK.COM hosts would be violating the requirement by using the "THINK.COM" nickname as part of the return address in their outgoing mail. If they did this anyway, then any host which DOES follow the rules when responding to these messages will generate headers addressed NOT to THINK.COM, but to GODOT.THINK.COM. And, of course, anyone responding to the secondary headers will never have seen any THINK.COM addresses! The solution that was adopted was simply to make THINK.COM the official name for one of their hosts. No nicknames. Note that as long as mail addresses are the equivalent of host addresses, the domain name system will still need to remember "old" names, so that the stuff in your mail files remains useful for a reasonable time after some host has changed its name. If people would like to discuss this further, I suggest using the HEADER-PEOPLE mailing list, as the problem is slightly more related to mail than to the workings of domain name servers. But since I used NAMEDROPPERS too for this message, I'll understand if others go through the same vacillation and settle on both... -------