nanog mailing list archives
Re: What DNS Is Not
From: Jack Bates <jbates () brightok net>
Date: Mon, 09 Nov 2009 17:26:16 -0600
Alex Balashov wrote:
When I write applications that make DNS queries, I expect the request to turn NXDOMAIN if the host does not exist - HTTP as well as non-HTTP, but especially non-HTTP.
Actually, the one I hate is when they return NXDOMAIN for any RR type other than A, breaking DNS. Most common is AAAA to return NXDOMAIN, which immediately has the effect of breaking the ability to fallback to A (why query for another RR, when the domain doesn't exist?). Several high end load balancers have the ability to do this according to the content providers I have addressed the matter with.
As a side note, any IPv6 capable stack which has determined there is IPv6 connectivity (through 6to4, native, teredo, etc) cannot access these sites. For an example (an ongoing issue) see www.txu.com. Responds to A, gives NXDOMAIN to AAAA.
I will not shame the high profile websites that have fixed their loadbalancers/DNS servers, but everyone on this list knows and has probably used them.
Jack
Current thread:
- RE: What DNS Is Not, (continued)
- RE: What DNS Is Not Jason Granat (Nov 11)
- Re: What DNS Is Not Patrick W. Gilmore (Nov 11)
- Re: What DNS Is Not sthaug (Nov 11)
- Re: What DNS Is Not Valdis . Kletnieks (Nov 11)
- Re: What DNS Is Not David Ulevitch (Nov 11)
- Re: What DNS Is Not Florian Weimer (Nov 12)
- Re: What DNS Is Not David Ulevitch (Nov 10)
- Re: What DNS Is Not Stephane Bortzmeyer (Nov 10)
- Re: What DNS Is Not sthaug (Nov 10)
- Re: What DNS Is Not David Ulevitch (Nov 10)
- Re: What DNS Is Not Jack Bates (Nov 09)
- Re: What DNS Is Not Patrick W. Gilmore (Nov 09)
- Re: What DNS Is Not Kevin Oberman (Nov 09)
- Re: What DNS Is Not Paul Vixie (Nov 12)
- RE: What DNS Is Not Warren Bailey (Nov 12)
- Re: What DNS Is Not bmanning (Nov 09)
- RE: What DNS Is Not Buhrmaster, Gary (Nov 09)
- Re: What DNS Is Not David Andersen (Nov 09)
- Re: What DNS Is Not bmanning (Nov 09)
- Re: What DNS Is Not Patrick W. Gilmore (Nov 09)
- Re: What DNS Is Not Edward Lewis (Nov 09)