nslookup Got recursion not available from... trying next server
Niall O'Reilly
Niall.oReilly at ucd.ie
Wed Jan 5 23:24:57 UTC 2011
On 05/01/11 21:36, vr wrote:
> I'm having a query problem and hope I'm at the right mailing list...
Formally, probably not, since what you describe isn't a BIND
issue. That said, the people on this list are likely among
those who can best give you helpful advice.
> I get a "recursion not available" message intermittently when using
> nslookup.
The short answer is, "Yes indeed: that's how DNS works."
A longer answer follows below.
I should mention first that I have no experience using
'nslookup'. I understand that it has a reputation for masking
the information actually needed for troubleshooting by trying
too hard to be "helpful". I don't actually know whether this
reputation is deserved.
I suggest you use 'dig' instead. I count myself lucky that
this was the first DNS troubleshooting tool I was introduced to
by our then "Internet expert" nearly 20 years ago. [Thanks,
Mike!] I've never felt the need to use another, and probably
haven't even yet discovered all of its features.
> The message will appear on the first query, presumably to
> un-cached IP/hostname and subsequent queries to the same IP/hostname
> will succeed without the message.
It is normal, and actually good practice, for any authoritative
name server (the master or slave for a given zone) to be
configured to refuse to provide recursive name service.
I guess that 'nslookup' is by default making a recursive query,
happens to send that query to an authoritative server, receives
a response in which the "recursion not available" flag is set,
and duly displays a message which appears at first sight to be
disturbing.
As it happens, 'dig' also makes a recursive query by default,
although it's easy to tell it not to. Besides, 'dig' just
shows the flags; it doesn't convert them into potentially
disturbing messages.
I hope this helps.
Best regards,
Niall O'Reilly
University College Dublin IT Services
More information about the bind-users
mailing list