On Tue, Aug 23, 2022 at 10:29 AM, Peter Thomassen <[email protected]> wrote:
> On 8/23/22 07:02, Ray Bellis wrote: > > There will be a very long tail of systems out there that do not know about > ".alt". > > How would those systems respond when passed a domain-style name that does > not meet domain-style syntax rules (specifically those for total length and > label lengths) ? > > Designers of that other non-DNS protocol will have to consider all kinds > of interoperability issues, including what kind of strings are permissible > under their branch of .alt, and what consequences would arise from that. > > IMO, that is within the realm of the specification of that other non-DNS > protocol, just like any other protocol consideration that occurs when > evolving a specification while implementing it; we DNS people don't have to > mandate fences for the general case. > Mandate no, but I do think that we should "helpfully suggest". There are many ways to refer to a host — for example, I recently had to ask someone to swap a drive in a server for me, and I resolved the identity with: "it's the Dell server towards the bottom of the rack near the door." Clearly this is a pathological case, but putting ".alt" at the end of that doesn't really help :-). Much of the reason for needing something like .alt is that the context isn't explicit, and so we expect that these names will be used in places that generally expect something like a "DNS name". I think that some text suggesting that for interoperability with existing applications (which may do some sort of checks or processing on the user input) people may want to constrain themselves to LDH / DNS syntax. There are no protocol police, and so we cannot actually enforce this even if we wanted to — I can technically put <bunny with big teeth emoji><somewhat bedraggled oxen emoji><sort of weird looking pyramid thingie emoji>.kumari.net into my zonefile, and there is nothing you can to do stop me… <mwahahaha, the power!!!> — but it sure won't work well… So, I'd think something like: "For compatibility with existing applications and to maximize interoperability, it is recommended that names that end in .alt follow DNS name syntax." (or something similar but better worded). W > Best, > Peter > > -- > https://desec.io/ > > _______________________________________________ > DNSOP mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/dnsop >
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