Agreed, here are the queries:
q=`jot -s . -b 123456789 25`.lu
for n in $(jot -c 13 a); do dig @${n}.root-servers.net $q +norec
+noquestion +noanswer +noauth +nocomment +nostat; done
There are 2 groups of additional sections:
A, C, E, I, J: 2 names, with their v4+v6 addresses
B, D, E, G, H, K, L, M: 4 names, only v4 addresses
What stroke me was 2 things:
- both groups do not change the answers on subsequent queries. So for
the first group, if the 2 servers are down, your done.
- the second group doesn't provide any v6 addresses at all.
Now I don't want to pick on any implementation, rather get an idea of
the reasoning behind the behaviour... (I do agree that the query is a
bit extreme). And if operators think that this might lead to problems.
Gilles
On 5/6/12 19:23 , Joe Abley wrote:
>
> On 2012-06-05, at 08:28, Gilles Massen wrote:
>
>> One set of root servers fills the additional section with 2 names, and
>> their v4 and v6 addresses. But it's always the same two servers,
>> indepently of the server asked. The other set answers with a bit more
>> servers, but only v4 adresses, and here again, always the same list.
>
> It might be instructive to spell out what query you tried, and what your
> results were (per letter).
>
> Some root servers are not shy about telling the world what software they are
> running, but others prefer to obfuscate:
>
> [krill:~]% for n in $(jot -c 13 a)
> for> do echo "${n}: $(dig @${n}.root-servers.net version.bind ch txt +short)"
> for> done
> a: "This space intentionally left blank"
> b: "4.8.1"
> c: "c-root"
> d: "9.8.1-P1"
> e:
> f: "9.7.4"
> g: ""
> h: "NSD 3.2.10"
> i: "contact i...@netnod.se"
> j: "This space intentionally left blank"
> k: "NSD 3.2.8"
> l: "NSD 3.2.8"
> m: "9.7.3-P3"
> [krill:~]%
>
> I can confirm the version string for L is accurate. The versions shown above
> for D, F, H, K and M look plausible to me, although I can't speak
> authoritatively about what they are doing.
>
> If you wanted to nail down the different behaviour to particular versions of
> software, the rootops are all here and will no doubt crawl out of the
> woodwork if there are questions to answer.
>
>
> Joe=
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