Re: [Doh] [Ext] DNS Camel thoughts: TC and message size
Dave Lawrence <tale@dd.org> Thu, 07 June 2018 16:54 UTC
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Date: Thu, 07 Jun 2018 12:54:16 -0400
From: Dave Lawrence <tale@dd.org>
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Subject: Re: [Doh] [Ext] DNS Camel thoughts: TC and message size
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Paul Hoffman writes: > Tony is completely correct here. DNS messages have well-defined > length limits: 512-or-more-depending if carried over UDP, and 65535 > if carried over TCP. Right. And completely undefined over any other transport. There is no intrinsic limit to the limit of a DNS message, compression pointers notwithstanding. I could give you a parser that would happily churn though a multi-megabyte DNS message. I was among the first advocating for making it clear that there needn't be an unnecessary limit imposed here, and I still stand by my position though at the moment it looks like I'll end up on the wrong side of consensus. My point is that when there is not a strict technical need driving some limit, I don't think it should be there. Have we learned nothing of scaling on the Internet over all these years? While "existing DNS message parsers might have a problem with it" is a legitimate potential issue, I don't see it as a compelling need to drive the requirement. It isn't even a given that all existing parsers would have a problem with it. In any event that's something that should be looked at by the programmer before just blindly pumping data through. There's even a use case for going beyond 64k, AXFR. Despite Tony's other message claiming that AXFR needs multiple messages, that's not fully accurate. I have plenty of zones that fit in a single DNS/TCP message when sent over AXFR, and DNS/HTTPS would cover the rest quite easily, except with a restriction on message lengths it actually makes things a bit more complicated. I will readily admit that I personally don't currently have a plan to start doing AXFR over DoH. My point is that this isn't just purely academic, but actually has some practical applications. My personal take is that, given that there is no strict technical limit for imposing a limit inside a transport that doesn't require it, the existing "any size" text should remain, and be augmented with a warning to developers about how that could be an issue with existing code that assumes no message can be greater than 64k based on earlier transport definitions.
- Re: [Doh] Are we missing an architecture? (was Re… Patrick McManus
- Re: [Doh] [Ext] Are we missing an architecture? (… Paul Hoffman
- Re: [Doh] [Ext] Are we missing an architecture? (… Mukund Sivaraman
- Re: [Doh] [Ext] Are we missing an architecture? (… Puneet Sood
- Re: [Doh] [Ext] Are we missing an architecture? (… Paul Hoffman
- Re: [Doh] [Ext] Are we missing an architecture? (… Ted Lemon
- Re: [Doh] [Ext] Are we missing an architecture? (… Ted Lemon
- Re: [Doh] [Ext] Are we missing an architecture? (… Paul Hoffman
- Re: [Doh] [Ext] Are we missing an architecture? (… Ted Lemon
- Re: [Doh] [Ext] Are we missing an architecture? (… Paul Hoffman
- Re: [Doh] [Ext] Are we missing an architecture? (… Mateusz Jończyk
- Re: [Doh] [Ext] Are we missing an architecture? (… Paul Hoffman
- Re: [Doh] [Ext] Are we missing an architecture? (… Sara Dickinson
- Re: [Doh] [Ext] Are we missing an architecture? (… Daniel Stenberg
- Re: [Doh] [Ext] Are we missing an architecture? (… Sara Dickinson
- Re: [Doh] [Ext] Are we missing an architecture? (… Daniel Stenberg
- Re: [Doh] [Ext] Are we missing an architecture? (… Mukund Sivaraman
- Re: [Doh] [Ext] Are we missing an architecture? (… Mukund Sivaraman
- Re: [Doh] [Ext] Are we missing an architecture? (… Ray Bellis
- Re: [Doh] [Ext] Are we missing an architecture? (… Patrick McManus
- Re: [Doh] [Ext] Are we missing an architecture? (… Mukund Sivaraman
- Re: [Doh] [Ext] Are we missing an architecture? (… Ben Schwartz
- Re: [Doh] [Ext] Are we missing an architecture? (… Mukund Sivaraman
- Re: [Doh] [Ext] Are we missing an architecture? (… Mukund Sivaraman
- Re: [Doh] [Ext] Are we missing an architecture? (… Ben Schwartz
- Re: [Doh] [Ext] Are we missing an architecture? (… Petr Špaček
- Re: [Doh] [Ext] Are we missing an architecture? (… Ray Bellis
- Re: [Doh] [Ext] Are we missing an architecture? (… bert hubert
- Re: [Doh] [Ext] Are we missing an architecture? (… Ray Bellis
- Re: [Doh] [Ext] Are we missing an architecture? (… Dave Lawrence
- Re: [Doh] [Ext] Are we missing an architecture? (… Dave Lawrence
- Re: [Doh] [Ext] Are we missing an architecture? (… Paul Hoffman
- Re: [Doh] [Ext] Are we missing an architecture? (… Tom Pusateri
- [Doh] DNS Camel thoughts: TC and message size bert hubert
- Re: [Doh] DNS Camel thoughts: TC and message size Petr Špaček
- Re: [Doh] DNS Camel thoughts: TC and message size Tony Finch
- Re: [Doh] DNS Camel thoughts: TC and message size Hewitt, Rory
- Re: [Doh] DNS Camel thoughts: TC and message size Benno Overeinder
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Andrew Sullivan
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Andrew Sullivan
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… George Michaelson
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Paul Hoffman
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Patrick McManus
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Tony Finch
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… bert hubert
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Paul Hoffman
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Martin J. Dürst
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Patrick McManus
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Paul Hoffman
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Tony Finch
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Dave Lawrence
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Dave Lawrence
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Patrick McManus
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Ray Bellis
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Ray Bellis
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… bert hubert
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Andrew Sullivan
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Dave Lawrence
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Dave Lawrence
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Robert Edmonds
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Dave Lawrence
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Dave Lawrence
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Mateusz Jończyk
- [Doh] AXFR as several messages Re: [Ext] DNS Came… bert hubert
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… John Dickinson
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Ray Bellis
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Mukund Sivaraman
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Mukund Sivaraman
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Patrick McManus
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Tony Finch
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Martin Thomson
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Mark Nottingham
- [Doh] DNS Camel thoughts: TC and message size Patrick McManus
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Ólafur Guðmundsson
- [Doh] Are we missing an architecture? (was Re: DN… Andrew Sullivan
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Dave Lawrence
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Andrew Sullivan
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… bert hubert
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Dave Lawrence
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Patrick McManus
- Re: [Doh] Are we missing an architecture? (was Re… Mark Nottingham
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Mukund Sivaraman
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Dave Lawrence
- Re: [Doh] Are we missing an architecture? (was Re… Andrew Sullivan
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Andrew Sullivan
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Patrick McManus
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Andrew Sullivan
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Patrick McManus
- Re: [Doh] [Ext] DNS Camel thoughts: TC and messag… Dave Lawrence
- Re: [Doh] Are we missing an architecture? (was Re… Dave Lawrence
- Re: [Doh] Are we missing an architecture? (was Re… bert hubert
- Re: [Doh] Are we missing an architecture? (was Re… Dave Lawrence
- Re: [Doh] [Ext] Are we missing an architecture? (… Ray Bellis