Redirecting Unresolved Domains to a Host

[Paul Vixie]

"Gaurav Pruthi" <gkpruthi at gmail.com> writes:

> I know it's not a good idea. But i want to give it to my few customers as
> per their requirement.  Only few of my customer will use that DNS for
> resolution of domains.  I trust it is possible but have no information
> about configuring it.
> 
> Please Advice

there is no BIND feature for this, and no underlying IETF DNS protocol
element for signalling it.  simply remapping NXDOMAIN into a response
runs the risk of sending non-HTTP traffic (P2P, e-mail, B2B, etc) to an
HTTP-only host.  ISC has historically avoided such features since while
they can help ISPs monetize user errors, they give no benefit to users
and in fact come at some risk and cost to users.

the best way to do this is, as marka said, to use policy routing and an
HTTP proxy that's configured to do some advertising-related thing when
an URI's domain does not exist (or perhaps even when the web server for
such a URI is not reachable.)  some such proxies even allow the real web
page to be put into a frame, surrounded by the ISP's own content.  if
your business model requires this kind of feature, then an HTTP proxy is
the right way to provide it.

there are also web browser plugins that your customers can install if as
you say this really is a customer requirement.

ISC would be willing to pursue this as a BIND feature if there was funding
for it and if the effort included an IETF DNS protocol extension so that
users could "opt in" to the feature, and so that any remapped responses
were clearly marked as having been remapped rather than as "real NXDOMAIN".

meanwhile ISC will continue to push for DNSSEC in the hope that this kind
of thing simply cannot be done at all in the way it's often done today
(using faked NXDOMAIN responses from full resolvers toward stub resolvers.)
-- 
Paul Vixie