I don't believe that's quite correct. A fully-qualified domain name has the trailing period. which is to say, 'first-hop.example.com.' which forces use of the top-level domain, and avoids resolving to e.g. a local .com.* domain set up within your local dns, which is possible alternate context. Anything else is only partially qualified. Even Wikipedia gets this right at the moment; quoting the page right now, at least until someone 'fixes' it: https://en.wikipedia.org/wiki/Fully_qualified_domain_name "Each subdomain is a child domain of every domain above it (its parent domain) and separated by a full stop. With the final full stop representing the root zone. Due to the lack of a label/name for this zone, it is often not represented in many softwares such as web browsers, resulting in a DNS hierarchy ending with the top-level domain with no trailing full stop. However, this is actually only a partially qualified domain name (PQDN), since we can fairly safely assume that we want to be using the same, agreed upon, root zone to interact with the domain we want (though there are alternate root zones)." RFC1035 could be clearer, and e.g. RFC4703 has been playing fast and loose with FQDN in its definitions. Lloyd Wood lloydwood@xxxxxxxxxxxxxxxxxxxxx On Wednesday, 31 August 2022 at 09:38:30 GMT+10, Fred Baker <fredbaker.ietf@xxxxxxxxx> wrote: A fully qualified domain name has no dependence on context - “first-hop.example.com” would be an example of a fully qualified domain name. Anything else - something that to be understood requires a reference to context - would not be fully qualified. Sent using a machine that autocorrects in interesting ways... > On Aug 30, 2022, at 12:47 PM, Keith Moore <moore@xxxxxxxxxxxxxxxxxxxx> wrote: > > On 8/30/22 15:41, Timothy Mcsweeney wrote: > >> I don't even know what 'non-fully qualified domain name' means. >> > I think they are in RFC1035 section 3?https://datatracker.ietf.org/doc/html/rfc1035#section-3.1 > Don't see them. Keith