DNS "A" query for a single dot

[Mark Andrews]

> On Mar 11 2008, Barry Margolin wrote:
> 
> >In article <fr4vdl$2c7l$1 at sf1.isc.org>, Mark <anonymoususr at gmail.com> 
> >wrote:
> >
> >> Hello ,
> >> 
> >> Does anybody knows what an "A" query for a dot (".") means?
> >
> >"." is the root domain.
> >
> >> Is it part of DNS and serve a special purpose?
> >> Is it a bug on the client making the query?
> >> Is it an indicative of a bot/worm making queries?
> >> 
> >> I am parsing the DNS packet using the name server library (function
> >> ns_initparse) and some  DNS packets have questions for "."
> >
> >I think there are a number of domains that have MX records pointing to 
> >the root, as a convention to prevent mail from being sent to the domain.
> 
> Positive incentive for some Evil Root Zone Administrator to set up
> an A record and trap all that e-mail, isn't it? No wildcard needed!
> 
> I also seem to recall lookups for (IN,A,".") being used by monitoring
> software to test whether nameservers are up or not. Not the best choice, 
> I thought.
> 
> -- 
> Chris Thompson
> Email: cet1 at cam.ac.uk
> 

	Also SRV except that it is something that is something that
	is supposed to be detected.

	Mark
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org