Re: [Doh] meta qtypes

Petr Špaček <> Mon, 19 March 2018 21:56 UTC

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Subject: Re: [Doh] meta qtypes
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On 19.3.2018 15:42, Dave Lawrence wrote:
> Tony Finch writes:
>> The problem with AXFR is [...] it [doesn't] fit into the
>> udpwireformat media type.
> Setting aside the other points you brought up ... it doesn't?
> I mean, sure, an AXFR would likely exceed UDP packet sizes typically
> seen in the wild, but why not a hypothetical jumbo packet,
> content-length mumblety-megabytes?  dns-udpwireformat is not defined in
> the doc as intrinsically limiting message length; multiple messages
> happen with DNS/TCP only because of the defined 64k limit for them.
> "udp" in the type only means "doesn't have the 16 bit prefix length".

Oh, but in that case the theoretical "proxy" would have re-assemble
answers from TCP connection to a DNS server into jumbo-message. Bleh,
please do not do this. DNS is complex as hell now and additional layer
of complexity in translation is going to be major pain.

Maybe we can get out first version without metatypes and add these later
on, if there is an actual demand for them.

Petr Špaček  @  CZ.NIC

> Does this too need to be made more explicit in the doc?  I don't
> recall any discussion of message size limits, or lack thereof