Re: [DNSOP] abandoning ANAME and standardizing CNAME at apex
Tony Finch <dot@dotat.at> Tue, 19 June 2018 14:20 UTC
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Date: Tue, 19 Jun 2018 15:20:48 +0100
From: Tony Finch <dot@dotat.at>
To: Petr Špaček <petr.spacek@nic.cz>
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Subject: Re: [DNSOP] abandoning ANAME and standardizing CNAME at apex
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Petr Špaček <petr.spacek@nic.cz> wrote: > > Given that resolver side somehow works already ... > could we standardize this obvious violation of RFC 1035? The feature I would like is CNAME and other data (typically CNAME + MX + TXT), because I have a lot of deeply hierarchial subdomains in my main zone. CNAME at apex does not need to be (and I think should not be treated as) a special case. As I understand it, in the RFC 883 era, CNAME was allowed to coexist with other records, but that led to consistency problems. eg, if you have a CNAME cached for a particular name, and you get a query for MX at the same name, do you go and ask the CNAME's owner or its target for the MX? And do you get a different answer to the MX query when you don't have a CNAME cached? My guess is that it was hard to fix this at the time because the semantics of negative cache entries was not well developed (e.g. RFC 1034 section 4.3.4 says it was still a new and experimental feature). For CNAME-with-siblings to work, a resolver needs to remember whether it already asked for the other data, for each RR type. 1980s caches couldn't do this, so CNAMEs were made exclusive instead. I think the resolver's algorithm for handling CNAMEs can be updated to allow CNAME-with-siblings and preserve compatibility. There will be some latency cost for later queries that can no longer immediately follow the CNAME shortcut. NSEC/NSEC3 records could be used to eliminate this cost. I'm much less sure about whether it's possible to publish CNAME-with-siblings in a reliably compatible way. I would feel a lot more comfortable with an ANAME implementation that copies the sibling records from the target to the owner when the zone is published or signed. Tony. -- f.anthony.n.finch <dot@dotat.at> http://dotat.at/ Trafalgar: Cyclonic, mainly northeasterly in northwest, 5 to 7. Slight or moderate until later in southeast, otherwise moderate or rough. Thundery showers, fog patches later. Moderate or good, occasionally very poor later.
- Re: [DNSOP] abandoning ANAME and standardizing CN… Evan Hunt
- Re: [DNSOP] abandoning ANAME and standardizing CN… Joe Abley
- Re: [DNSOP] faux BNAME, was abandoning ANAME and … John Levine
- Re: [DNSOP] abandoning ANAME and standardizing CN… Tony Finch
- Re: [DNSOP] abandoning ANAME and standardizing CN… John Levine
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Vixie
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mark Andrews
- Re: [DNSOP] abandoning ANAME and standardizing CN… Ray Bellis
- Re: [DNSOP] abandoning ANAME and standardizing CN… Jan Včelák
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mark Andrews
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Ebersman
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mark Andrews
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mark Andrews
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Vixie
- Re: [DNSOP] abandoning ANAME and standardizing CN… David Conrad
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Vixie
- Re: [DNSOP] abandoning ANAME and standardizing CN… Tony Finch
- Re: [DNSOP] abandoning ANAME and standardizing CN… Tony Finch
- Re: [DNSOP] abandoning ANAME and standardizing CN… Ray Bellis
- Re: [DNSOP] abandoning ANAME and standardizing CN… Ondřej Surý
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Wouters
- Re: [DNSOP] abandoning ANAME and standardizing CN… Matthew Pounsett
- Re: [DNSOP] abandoning ANAME and standardizing CN… Joe Abley
- Re: [DNSOP] abandoning ANAME and standardizing CN… John Levine
- Re: [DNSOP] abandoning ANAME and standardizing CN… Tony Finch
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Vixie
- Re: [DNSOP] abandoning ANAME and standardizing CN… Colm MacCárthaigh
- Re: [DNSOP] abandoning ANAME and standardizing CN… Tony Finch
- Re: [DNSOP] abandoning ANAME and standardizing CN… Tony Finch
- Re: [DNSOP] abandoning ANAME and standardizing CN… Anthony Eden
- Re: [DNSOP] abandoning ANAME and standardizing CN… Erik Nygren
- Re: [DNSOP] abandoning ANAME and standardizing CN… Ray Bellis
- Re: [DNSOP] abandoning ANAME and standardizing CN… Jared Mauch
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Wouters
- Re: [DNSOP] abandoning ANAME and standardizing CN… Ray Bellis
- Re: [DNSOP] abandoning ANAME and standardizing CN… Tony Finch
- Re: [DNSOP] abandoning ANAME and standardizing CN… Joe Abley
- Re: [DNSOP] abandoning ANAME and standardizing CN… Lanlan Pan
- Re: [DNSOP] abandoning ANAME and standardizing CN… tjw ietf
- Re: [DNSOP] abandoning ANAME and standardizing CN… Colm MacCárthaigh
- Re: [DNSOP] abandoning ANAME and standardizing CN… Tony Finch
- [DNSOP] abandoning ANAME and standardizing CNAME … Petr Špaček
- Re: [DNSOP] abandoning ANAME and standardizing CN… Tony Finch
- Re: [DNSOP] abandoning ANAME and standardizing CN… Tony Finch
- Re: [DNSOP] abandoning ANAME and standardizing CN… Ray Bellis
- Re: [DNSOP] abandoning ANAME and standardizing CN… Viktor Dukhovni
- Re: [DNSOP] abandoning ANAME and standardizing CN… Evan Hunt
- Re: [DNSOP] abandoning ANAME and standardizing CN… Joe Abley
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Vixie
- Re: [DNSOP] abandoning ANAME and standardizing CN… Shumon Huque
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Vixie
- Re: [DNSOP] abandoning ANAME and standardizing CN… Joe Abley
- Re: [DNSOP] abandoning ANAME and standardizing CN… Viktor Dukhovni
- Re: [DNSOP] abandoning ANAME and standardizing CN… Evan Hunt
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Vixie
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mark Andrews
- Re: [DNSOP] abandoning ANAME and standardizing CN… 神明達哉
- Re: [DNSOP] abandoning ANAME and standardizing CN… Tony Finch
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Vixie
- Re: [DNSOP] abandoning ANAME and standardizing CN… Shumon Huque
- Re: [DNSOP] abandoning ANAME and standardizing CN… Warren Kumari
- Re: [DNSOP] abandoning ANAME and standardizing CN… John R Levine
- Re: [DNSOP] abandoning ANAME and standardizing CN… Evan Hunt
- Re: [DNSOP] abandoning ANAME and standardizing CN… Lanlan Pan
- Re: [DNSOP] abandoning ANAME and standardizing CN… Evan Hunt
- Re: [DNSOP] abandoning ANAME and standardizing CN… John R Levine
- Re: [DNSOP] abandoning ANAME and standardizing CN… Evan Hunt
- Re: [DNSOP] abandoning ANAME and standardizing CN… Warren Kumari
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mukund Sivaraman
- Re: [DNSOP] Creating a query/record for A and AAAA Paul Vixie
- Re: [DNSOP] Creating a query/record for A and AAAA Michael Sheldon
- Re: [DNSOP] Creating a query/record for A and AAAA Paul Vixie
- [DNSOP] Creating a query/record for A and AAAA Michael Sheldon
- Re: [DNSOP] Creating a query/record for A and AAAA Paul Wouters
- Re: [DNSOP] Creating a query/record for A and AAAA Mark Andrews
- Re: [DNSOP] Creating a query/record for A and AAAA Tony Finch
- Re: [DNSOP] Creating a query/record for A and AAAA Ondřej Surý
- Re: [DNSOP] Creating a query/record for A and AAAA Jared Mauch
- Re: [DNSOP] Creating a query/record for A and AAAA Paul Wouters
- Re: [DNSOP] Creating a query/record for A and AAAA Ray Bellis
- Re: [DNSOP] Creating a query/record for A and AAAA Ray Bellis
- Re: [DNSOP] Creating a query/record for A and AAAA Paul Vixie
- Re: [DNSOP] abandoning ANAME and standardizing CN… Tim Wicinski
- Re: [DNSOP] abandoning ANAME and standardizing CN… Brian Dickson
- Re: [DNSOP] abandoning ANAME and standardizing CN… Tony Finch
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Hoffman
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Vixie
- Re: [DNSOP] abandoning ANAME and standardizing CN… Matthijs Mekking
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mukund Sivaraman
- Re: [DNSOP] abandoning ANAME and standardizing CN… Paul Vixie
- Re: [DNSOP] abandoning ANAME and standardizing CN… Dan York
- Re: [DNSOP] abandoning ANAME and standardizing CN… Evan Hunt
- Re: [DNSOP] abandoning ANAME and standardizing CN… Stephane Bortzmeyer
- Re: [DNSOP] abandoning ANAME and standardizing CN… Stephane Bortzmeyer
- Re: [DNSOP] abandoning ANAME and standardizing CN… Ray Bellis
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mukund Sivaraman
- Re: [DNSOP] abandoning ANAME and standardizing CN… Ray Bellis
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mukund Sivaraman
- Re: [DNSOP] abandoning ANAME and standardizing CN… Petr Špaček
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mukund Sivaraman
- Re: [DNSOP] abandoning ANAME and standardizing CN… Evan Hunt
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mukund Sivaraman
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mark Andrews
- Re: [DNSOP] abandoning ANAME and standardizing CN… JW
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mark Andrews
- Re: [DNSOP] abandoning ANAME and standardizing CN… Petr Špaček
- Re: [DNSOP] abandoning ANAME and standardizing CN… Stephane Bortzmeyer
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mukund Sivaraman
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mark Andrews
- Re: [DNSOP] abandoning ANAME and standardizing CN… Petr Špaček
- Re: [DNSOP] abandoning ANAME and standardizing CN… Mukund Sivaraman