name server via dhcp, but don't want dhcp assigned addresses

[James Wilkinson]

Joel Rees wrote:
> I have ADSL, with a "modem"/router that does filtering, dhcp, etc.
> Since I want to refer to the boxes on the internal LAN (natted to
> local-address subnet) by name, I have the router set to only
> automatically allocate a piece of the subnet. Usually, all of the
> internal machines have their IP addresses set statically, thus, to
> addresses not included in the automatic portion of the subnet.
> 
> The WAN side of the router runs dhcp to my ISP, and gets the dns
> server addresses by dhcp, as well.
> 
> In the past, the ISP had told us to set the primary and secondary
> dns server addresses statically, so I had the router set to serve
> dhcp with those address. But I have also set the dns primary and
> secondary server addresses for all the boxes by hand to the dns
> servers provided by my ISP, so that I was ignoring the dns servers
> provided by the router.
> 
> Recently, my ISP (a middle-rank provider in Japan) sent around
> notices that they were changing their setup, such that the dns
> servers would be advertised by dhcp and subject to change. That is,
> they said, more or less, "Clear the addresses you've set as your DNS
> servers in the DCHP client dialogs" (with example screen shots of
> Macs and MSWindows DHCP client dialogs) "so that you get the DNS
> addresses provided by the DHCP servers."
> 
> On the Macs, there is an option to set the box as a DHCP client with
> static IP address, so I can still keep that much of my lan intact.
> But the Fedora boxes do not provide a static IP address client as a
> setting in the standard dialogs, as far as I can tell.
> 
> So, my problem is that I need to tell each Fedora box to accept the
> DNS server addresses provided by the DHCP server (the router,
> actually, which worries me), but not ask for a host IP address for
> itself, but the GUI dialogs in current Fedora don't provide that as
> an option.
> 
> Am I just missing something there, or will I need to disable the GUI
> and dig into text configuration files in /etc/dhclient.d? (nis.sh
> and ntp.sh don't seem to be the files I need.)

Normally, these routers will have a basic DNS server built-in (which
will query the DNS servers that the router gets through DHCP). Have you
tried replacing the primary and secondary DNS server addresses with the
internal IP address of your router?

Alternatively, can you persuade your router to offer static DHCP leases
(so each MAC address always gets the same IP address)?

Hope this helps,

James.

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