slow lookup to non-existent host
Barry Margolin
barmar at alum.mit.edu
Sat Oct 16 02:48:46 UTC 2010
In article <mailman.490.1287172931.555.bind-users at lists.isc.org>,
Eric Ritchie <eritchie at interactivebrokers.com> wrote:
> When doing a nslookup of a non-existent host on the same network as
> the bind servers, there is a delay. If I do the same nslookup from a
> host on a different network, the response is immediate.
My guess is that the server allows recursion for clients on the same
network, but doesn't allow it for clients on a different network. But
there's something blocking its ability to recurse.
>
> host a is on the same network as bind servers, host b is on different
> network:
>
> hostb$ nslookup dev600
> Server: 131.210.30.200
> Address: 131.210.30.200#53
>
> ** server can't find dev600: REFUSED
>
> hosta $ nslookup dev600
> ;; connection timed out; no servers could be reached
>
> tcpdump on server:
> 15:53:38.535453 IP hosta.ibg.28346> bindsrv.domain: 36663+ A? dev600.ibg.
> (28)
> 15:53:38.535582 IP bindsrv.domain> hosta.ibg.28346: 36663 NXDomain* 0/1/0
> (75)
> 15:53:38.535834 IP hosta.ibg.23719> bindsrv.domain: 44929+ A? dev600. (24)
>
>
> 15:53:21.233381 IP hostb.ibg.51921> bindsrv.domain: 38869+ A? dev600.ibg.
> (28)
> 15:53:21.233750 IP bindsrv.domain> hostb.ibg.51921: 38869 NXDomain*- 0/1/0
> (75)
> 15:53:21.234022 IP hostb.ibg.43283> bindsrv.domain: 41973+ A? dev600. (24)
> 15:53:21.234181 IP bindsrv.domain> hostb.ibg.43283: 41973 Refused- 0/0/0
> (24)
>
>
> We have several locations with similar setups and all see the same
> issue. They are running different versions also, one is 9.4.2 and one is
> 9.7.0-P1. The /etc/resolv.conf file is:
>
> search ibg
> options rotate
> options ndots:3
> nameserver 131.210.30.200
> nameserver 131.210.30.201
> nameserver 131.210.30.202
> nameserver 131.210.30.203
>
> Thanks
--
Barry Margolin, barmar at alum.mit.edu
Arlington, MA
*** PLEASE don't copy me on replies, I'll read them in the group ***
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