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Re: Retry mechanism w/ DNS Format Error?
On Wed, 5 Jan 2005, Ulrich Drepper wrote:
Pekka Savola wrote:
Now, apparently the RHL9 resolver code cannot cope with FormErr code
quickly, but has to resort to timeouts. (I've been unable to verify this
on a newer glibc because it no longer creates the bitstring queries,
Sure they do, if use tell it. Set the ip6-bytestring option in resolv.conf.
OK, good to know; I didn't realize this support was still there as
optional :)
Anyway, I tried to reproduce it, but your server is not accessible to me. I
took only a brief look at the code. In the one place where FORMERR is
handled, it marks the error as not recoverable. I'm not sure whether this is
the right place or whether unrecoverable errors are handled appropriately.
As long as I cannot reproduce it I cannot do much unless you provide detailed
information about the code flow for these responses.
And please file any such reply in bugzilla, else it might get lost.
The server is stock BIND 9.3.0, where they removed the support for
bytestring queries. I think there are lots of servers out there (and
more on the way), but if you want to test with one, you can use
"gap.netcore.fi". It doesn't do much of anything, but should send
FormErr messages for bitstring queries..
Unfortunately I don't have a newer glibc system handy just yet to do
any testing myself, maybe next week unless you or someone else has
reproduced this by then.
--
Pekka Savola "You each name yourselves king, yet the
Netcore Oy kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings