Strange DNS Resolution Issues

[Barry Margolin]

In article <griomf$jrj$1 at sf1.isc.org>,
 Revital Gorsht <revital at yorku.ca> wrote:

> I'm not sure how to check this.  Some other ones that were failing: 
> cisco.com, hotmail.com. 

dig www.cisco.com

;; ANSWER SECTION:
www.cisco.com.    1377  IN CNAME www.cisco.com.akadns.net.
www.cisco.com.akadns.net. 32  IN CNAME origin-www.cisco.com.
origin-www.cisco.com.   33366 IN A  198.133.219.25

dig www.hotmail.com

;; ANSWER SECTION:
www.hotmail.com.  2208  IN CNAME mail.live.com.
mail.live.com.    3128  IN CNAME toplevel.mail.live.com.akadns.net.
toplevel.mail.live.com.akadns.net. 580 IN CNAME origin.mail.live.com.
origin.mail.live.com.   2058  IN A  64.4.20.169
origin.mail.live.com.   2058  IN A  64.4.20.184
origin.mail.live.com.   2058  IN A  64.4.20.186
origin.mail.live.com.   2058  IN A  64.4.20.174

> 
> But, if the problem was external, all of our servers (and others around 
> the world) would've been unable to resolve these sites, no?  As I 
> mentioned, only two were failing while the rest were resolving properly.

Maybe those two servers had cached something bad in the delegation to 
akadns.net.  It's hard to say after the fact.  If it happens again, dump 
your cache.

> 
> 
> 
> 
> Barry Margolin <barmar at alum.mit.edu> 
> Sent by: bind-users-bounces at lists.isc.org
> 08/04/2009 01:39 PM
> 
> To
> comp-protocols-dns-bind at isc.org
> cc
> 
> Subject
> Re: Strange DNS Resolution Issues
> 
> 
> 
> 
> 
> 
> In article <grgauk$1udj$1 at sf1.isc.org>,
>  Revital Gorsht <revital at yorku.ca> wrote:
> 
> > A few weeks ago, two of several internal DNS servers were suddenly 
> unable 
> > to resolve some external sites (eg microsoft.com, yahoo.com), while all 
> > internal and other external sites (eg google.com) were resolving fine. 
> > Since we couldn't pinpoint the cause, the problem went on for about 5 
> > hours and then magically fixed itself... we were all left scratching our 
> 
> > heads.
> 
> Both those domains use CNAME chains that go through akadns.net.  Was 
> this common to all the domains you had problems with?
>

-- 
Barry Margolin, barmar at alum.mit.edu
Arlington, MA
*** PLEASE don't copy me on replies, I'll read them in the group ***