Forwarding to mulitple DNS thru cable modem link

[Kevin Darcy]

"netnews.insightbb.com" wrote:

> Here is my setup:
>     I have a FreeBSD 4.6 box running natd and bind acting as a router and
> dns for my home network.  My network is connected thru a cable modem to the
> internet which in turn has a vpn running to work.  My BIND installation is
> forwarding all queries to the 2 DNS Servers on the ISP's network.  Can I
> have my install of bind forward all requests for the internet to my isp's
> dns and all requests to the VPN to the dns at work?  How?

If your IP routing is set up such that packets from your BIND box destined for
the nameservers on your "work" network will automatically route correctly over
the VPN, then it should be possible to set up your "work" domains as
slave/forward/stub zones in BIND, pointing to your "work" nameservers. This
information will then override anything you would otherwise resolve over the
Internet without interfering with any non-"work", i.e. Internet, name
resolution.

> My next question:
> By doing this can I plug my work laptop into my home network's switch and
> have the dhcp hand out the proper information needed to resolve to the vpn's
> dns?

Not if you're running just a plain old "stub" resolver on the work laptop,
since in that case it's not capable of routing queries for different domains to
different nameservers -- stub resolvers just send *every* query to the same
DHCP-derived list of nameservers, failing over from one to the next if it gets
no answer.

Now, if the laptop is running a real OS, maybe you could run a BIND nameserver
on it, in which case you could configure it as described above. But, it
*still* wouldn't be getting the addresses of the forwarders/masters via DHCP:
you'd have to manually configure those into named.conf.


- Kevin