[dns-operations] Reporting glue as authoritive data -- Bug!
Edward Lewis
Ed.Lewis at neustar.biz
Wed Jan 30 14:10:37 UTC 2008
At 9:47 +1100 1/30/08, Mark Andrews wrote:
> Diversity in answers is bad for the resolver as they have
> to deal with all the undocumented crud that gets sent at
> them.
Putting the cart before the horse, I don't think anyone has said that
diversity in answers is a desired state. The fact is that it
happens. The fact that DNS can deal with it is one of its strengths.
>
> We already have to have a workaround to deal with this
> "referral in answer". Yes, BIND 8 produced this crud
> as well.
The point that seems to be getting lost is not that hybrid answers
are produced but that there are resolvers that need it. I received a
bit more detail on our (Ultra's) experience. The behavior as it is
now dates back to last century, a few years ago a fix was put in
place. The result was the production network got hammered due to a
resolver bug, so it was backed out. The problem today is that we
have been unable to verify that adding the fix back in wouldn't
repeat the situation.
Nevertheless, I think it is worth documenting this message. Right
now I don't have the time, I want to knock out AXFR first. Is there
a problem documenting current, observed, in existence operational
behavior?
>; <<>> DiG 9.3.4-P1 <<>> ns uu.net +norec @a.gtld-servers.net
>; (2 servers found)
>;; global options: printcmd
>;; Got answer:
>;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30839
>;; flags: qr; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 4
>
>;; QUESTION SECTION:
>;uu.net. IN NS
>
>;; ANSWER SECTION:
>uu.net. 172800 IN NS auth00.ns.uu.net.
>uu.net. 172800 IN NS auth200.ns.uu.net.
>uu.net. 172800 IN NS auth210.ns.uu.net.
>uu.net. 172800 IN NS auth60.ns.uu.net.
>
>;; ADDITIONAL SECTION:
>auth00.ns.uu.net. 172800 IN A 198.6.1.65
>auth200.ns.uu.net. 172800 IN A 195.129.12.82
>auth210.ns.uu.net. 172800 IN A 195.129.12.74
>auth60.ns.uu.net. 172800 IN A 198.6.1.181
>
>;; Query time: 283 msec
>;; SERVER: 2001:503:a83e::2:30#53(2001:503:a83e::2:30)
>;; WHEN: Wed Jan 30 09:37:03 2008
>;; MSG SIZE rcvd: 177
>
> I'm sure if I look hard enough I'll find a glue in answer
> without glue in additional as well.
What are you looking for?
--
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Edward Lewis +1-571-434-5468
NeuStar
Think glocally. Act confused.
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