On 23/03/18 14:44, Miles Fidelman wrote: > Christ, Richard :-) > why are we still discussing this. (And what does it have to do > with the original question about "Federated, decentralised communication > on the internet?" ... which was originally a question about how > "hostname" is used by Debian) Agreed. Apologies for the deviation. > But... > > An FQDN defines the location of an entity in the DNS tree. For a host - > which is what we've been discussing, and generally what one is talking > about when talking about FQDN's an FQDN consists of both a hostname AND > a domain name. (Again, in the Linux context, one is generally making > the distinction between "hostname," "network name," and "fully qualified > domain name" - often in the context of setting up a machine, or the > "hostname" and "dnsdomainname" commands, "hostname --fqdn", or the files > where such information is stored.) > > When it comes to hosts, it is generally understood that the FQDN > consists of both the hostname and domainname, and an awful lot of > protocol specs cite (and quote) https://tools.ietf.org/html/rfc1983 - > the "Internet Users' Glossary" which says... > > Fully Qualified Domain Name (FQDN) > The FQDN is the full name of a system, rather than just its > hostname. For example, "venera" is a hostname and > "venera.isi.edu" is an FQDN. See also: hostname, Domain Name > System. Another reference, thanks. Still not specific. > Now, arguably, "." is an FQDN specifying the very top of the DNS tree, > and "com" (or "com.") specifies the top of the com domain - but who > really cares. Particularly since the whole discussion started around > fully qualified HOST names. This is my point. And AFAIK DNS would happily accept an A record for com, and probably . too. (I haven't tried it in BIND; I should ...) > Another common definition of an FQDN is that it uniquely identifies a > node in the DNS tree. By that view "." is the FQDN for the top of the > tree, and "com" (or "com." is the top of the .com domain - but who > really cares, except for pedantic purposes. When talking about specs and RFCs (which maybe only I was), surely pedantic purposes are what it's all about? > There aren't any > nameservers that resolve "." or "com" or "mil" - implying that there are > no records in the system for them (maybe there should be, but that's > another question for another day). There might not be A, AAAA or MX records, but there are certainly servers, and they serve at least SOA and NS (and RRSIG) records for all 3 of those. Again, apologies for the aside that got a bit carried away. Richard
Attachment:
signature.asc
Description: OpenPGP digital signature