Re: thousands of RFails bring namserver down

wolf_qwert wrote:

> Hi,
>
> I am running a bind8 nameserver and have a problem with thousands of
> queries to my  nameserver for a nameserver that currently seems to be
> down. During the last hour the RFail count went up 698202! My
> nameserver gets the queries from one client (and my problem is, that I
> don't have access to this client) and starts to send every query out -
> waits for the timeout and tries again. In the end the server sends the
> query back unanswered to the client as it should. The result is that
> the CPU is at 100% and no normal query gets answered in an aceptable
> time. Now I have 3 questions:
> 1.Is there no way to tell the named to cache the information that the
> nameserver is currently not answering?

No, not as such. You could, however, mark the nameserver as "bogus" in
your named.conf.

>
> 2.Should not the client store the information that the server is not
> available?

Depends on the client. Traditionally, "stub resolvers" don't cache
anything. Even those that *do* cache generally only cache positive
results.

> 3.Is there a client that is known for sending thousands of queries if
> it gets no correct answer?

If this is a stub resolver, then the frequency of queries would be
entirely up to the local application which is generating them. And there
is, of course, practically an infinite variety of applications out there:
you'd probably know much better than we would what apps are likely to be
running on that box...


- Kevin