[GRLUG] dns hijacking

[Michael Mol]

On Thu, Aug 13, 2009 at 1:44 PM, john-thomas richards<jtr at jrichards.org> wrote:
> On Thu, Aug 13, 2009 at 11:09:26AM -0400, Benjamin Flanders wrote:
>> I've tried OpenDNS multiple times but it seems to have a lot of
>> issues.  A couple times a week it couldn't find google.com or more
>> often than that it had trouble finding about half of the Google maps
>> tiles  I would have to refresh about 3 times for all the map to show
>> up.  This was a while ago so maybe they have fixed things.
>
> I'm wading into things I really don't have the chops to discuss, but how
> would that be an OpenDNS problem?  Since you were able to load part of
> the map, you were able to get to maps.google.com.  (This may be a
> *really* dumb question, I admit.)

Because the image files aren't served up from maps.google.com.

Each time you load an image from a website, if the website has
previously assigned a cookie, your browser is supposed to send that
cookie back to the server.  For a website that serves up tens of
thousands of requests per second, that's a lot of cookies being sent
back, and a lot of bandwidth consumed.

To get around it, sites like ImageShack, Flickr, Google, Yahoo, et al
like to put the images on a domain that your browser won't send the
cookie to.

For load balancing purposes, many such domains may be used.  So if
your DNS provider isn't entirely reliable, one of those DNS requests
might fail temporarily.

-- 
:wq