ad.doubleclick.net missing from DNS?

Wed Jul 28 14:57:51 UTC 2004

On 7/27/2004 6:21 PM, John Palmer wrote:

> Now the question is, can one easily block all of doubleclick.net

Couple of methods that have worked for me.

If you have squid or similar, you can get a plugin that lets you redirect
various sites/domains to a 1x1 transparent gif. This method is preferred
since it only requires a single list to maintain.

If you have a local nameserver and webserver, then make your dns server
authoritative for the domains and redirect queries to a sink address on
the web server, and config the web server to answer such requests with
that 1x1 transparent gif object. This is more difficult (have to maintain
the named.conf list of domains and the apache list of virtual hosts) but
overruling the domain names has a lot of potential power for other uses
too, possibly including spam blocking, if you are so configured.

In both cases, the gif mime-type will overwrite whatever content was
originally specified, and the gif is scaled to whatever is specified by
the html layout, so using a 1x1 transparent gif doesn't usually cause
problems.

The hard part here is managing the list of blocked sites, restarting the
service, etc.

And like Paul said, think about the ramifications of providing such
features to a secondary organization and/or user. Making them manually
configure their proxy/resolver settings may be enough, but IANAL.