Root server cannot be a forwarder?
kcd at daimlerchrysler.com
Thu Oct 19 22:39:52 UTC 2006
yinzhang57 at yahoo.com wrote:
> Peter Dambier wrote:
>> yinzhang57 at yahoo.com wrote:
>>> Heard that on a BIND root server, recursion is disabled and it will not
>>> do recursion, therefore cannot be a forwarder?
>> It depends on what you want to do.
>> E.g. my own BIND 9.4.0b2 is my local resolver.
>> I believe that domains I am authoritative for, cannot get cache poisoned.
>> That is why I am slaving every important domain I can.
>> It slaves the root too.
>> To prevent bogus queries like localhost, local, or 192.168... from
>> escaping my network. I am authoritative for those domains.
>> Some poor people on backwater domains have only a single nameserver.
>> Sometimes those domains get lost. I have a local copy and I am
>> authoritative. I need not even query for those domains.
>> The root zone is just a very little domain compared to com, net or org.
>> I never need to query the root-servers.
>> I rarely need to axfr a zone. I never query those zones. So I spare
>> them a lot of traffic.
>> As the root is already loaded I very often drop one query level and
>> my answers are faster.
>> Zones I need are present locally. No query to the outside at all.
>> But my server is not for the public. It serves locally only.
>> If I was running a root-server for the public, I would run nothing
>> but the root. I definitely would switch recursion off because I
>> am not a resolver.
>> Kind regards
>> Peter and Karin Dambier
>> Peter and Karin Dambier
>> Cesidian Root - Radice Cesidiana
>> Von-Erthal-Strasse 4
>> D-64646 Heppenheim
>> +49(6252)671-788 (Telekom)
>> +49(6252)750-308 (VoIP: sipgate.de)
>> mail: peter at peter-dambier.de
>> mail: peter at echnaton.serveftp.com
> Is a BIND root server by default disabled recursion, so cannot be a
Why do you think that a root nameserver acts fundamentally different
than a non-root nameserver? In named.conf terms, a master or slave
definition for the root zone is really no different than a master or
slave definition for any other zone.
So, again, the answer is: being a root nameserver does not cause BIND to
disable recursion. If you want to turn off recursion, you need to do
> A Windows root server by default disable to forward, to be a forwarding
> server. A BIND root server will still be able to act as a forwarding
Yes it can act as a forwarding server, subject to the caveats I gave in
my previous message, i.e. whatever it's forwarding must be either
delegated from the root zone, or have an appropriate zone definition at
a lower level of the namespace tree. A root server cannot be a "general"
forwarder, i.e. forward whatever it can't find, because anything that
doesn't fall into one of the two categories above will be considered to
be in the root zone, and a root nameserver will answer definitively from
the root zone, without forwarding. This is just a special case of the
general rule that a BIND nameserver will never forward queries which are
in a zone for which it is authoritative.
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