recursive queries fail with high load?

[Ross Vandegrift]

On Sun, Feb 25, 2007 at 10:31:16PM -0700, Chris Michels wrote:
> I have 3 DNS servers running bind 9.3.2.  Two of them are failing to resolve
> recursive queries.   Both of these servers have a higher load because they
> are used by our spam filtering software.

Check that your spam filtering software respects a fully-qualified
name as fully qualified.  I've seen DNS servers get beat down pretty
badly by spam filtering software that insisted on looking up
x.spamhaus.org.domain.com., x.spamcop.net.domain.com, etc, for each
domain.com in the search list.  These are all going to fail, and it
can be quite a load.

Our caching nameservers now think that they are authoritative for
these zones ::-).

-- 
Ross Vandegrift
ross at kallisti.us

"The good Christian should beware of mathematicians, and all those who
make empty prophecies. The danger already exists that the mathematicians
have made a covenant with the devil to darken the spirit and to confine
man in the bonds of Hell."
	--St. Augustine, De Genesi ad Litteram, Book II, xviii, 37