Seeking only some information by DHCP

This is probably a FAQ, but I couldn't find it answered. The problem is
common enough that there must be a solution out there.

I have a client machine (SuSE 9.3) which I would like to have a fixed IP
for, but for it to get other information (particularly name servers)
from the DHCP server.

Before you say that I should just configure the DHCP server to assign a
specific IP to a particular MAC address, please understand that I have
very very little control over the DHCP server. The DHCP server is an
SMC8013WG with Comcast's own tinkering of the firmware.

So, I need to do this from the client side.

I was hoping that there would be a simple configuration option through
YaST to set IP manually, while getting everything else through DHCP. If
there is please point me to it.

If there isn't a simple Push Here Dummy way of doing it, I can think of
several alternatives of off the top of my head, but none seem
particularly pretty.

(1) One of the few things I can do with the DHCP server is set lease
times. One option is "forever". I could let my machine get its IP from
DHCP, and then hope that it sticks with that IP for a long time.
(Considering how often I have to reboot the SMC8013WG, I really think
that this would be a very bad idea.

(2) Run bind locally. Set it up as a forwarder, and cobble together
some sort of start up script that queries DHCP and puts the information
into a named configuration file.

(3) Write a start up script that queries DHCP and puts the information
into /etc/resolve.conf

Now of course (3) would be easier than (2), but eventually I'd like to
run named somewhere on my local network for internal domains.

I'm sure that this is a common problem, so there must be well thought
out solutions to it.

-j

On Fri, 23 Sep 2005 20:48:07 -0500, Jeffrey Goldberg wrote:

> I have a client machine (SuSE 9.3) which I would like to have a fixed IP
> for, but for it to get other information (particularly name servers)
> from the DHCP server.

Why not keep it with a fixed (static) IP, and enter the name server
information yourself (in /etc/resolv.conf). No need to mess with DHCP at
all.

--
If you're not on the edge, you're taking up too much space.
Linux Registered User #327951

Dan C wrote:
> On Fri, 23 Sep 2005 20:48:07 -0500, Jeffrey Goldberg wrote:
>
>> I have a client machine (SuSE 9.3) which I would like to have a fixed IP
>> for, but for it to get other information (particularly name servers)
>> from the DHCP server.
>
> Why not keep it with a fixed (static) IP, and enter the name server
> information yourself (in /etc/resolv.conf). No need to mess with DHCP at
> all.

Because I'm not confident that Comcast will keep the same name servers
up and running. But yes, that is an obvious option. I should just do
that until something breaks. Still the feature I want should be
available. I don't wish to start an OS war, but another popular Unix
system has exactly this feature (configure IP manually, everything else
from DHCP), and I guess I've grown used to it.

Thanks

Dan C wrote:

> Why not keep it with a fixed (static) IP, and enter the name server
> information yourself (in /etc/resolv.conf). No need to mess with DHCP at
> all.

An even better solution turns out to be that the comcast provided router
acts as a forwarding DNS server itself. I simply hadn't noticed that
before. But I've just confirmed it works. So I can put my gateway in
as nameserver and not have to worry about comcast changing nameservers
on me.

Sorry for the trouble. It seems to be the case that one solves a
problem shortly after posting to Usenet.

-j

On Fri, 23 Sep 2005 21:27:33 -0500, Jeffrey Goldberg wrote:

>> Why not keep it with a fixed (static) IP, and enter the name server
>> information yourself (in /etc/resolv.conf). No need to mess with DHCP at
>> all.

> An even better solution turns out to be that the comcast provided router
> acts as a forwarding DNS server itself. I simply hadn't noticed that
> before. But I've just confirmed it works. So I can put my gateway in
> as nameserver and not have to worry about comcast changing nameservers
> on me.

Cool.

> Sorry for the trouble. It seems to be the case that one solves a
> problem shortly after posting to Usenet.

No trouble at all, glad you got her figured out.

--
If you're not on the edge, you're taking up too much space.
Linux Registered User #327951

Dan C wrote:

> On Fri, 23 Sep 2005 20:48:07 -0500, Jeffrey Goldberg wrote:
>
>> I have a client machine (SuSE 9.3) which I would like to have a fixed IP
>> for, but for it to get other information (particularly name servers)
>> from the DHCP server.
>
> Why not keep it with a fixed (static) IP, and enter the name server
> information yourself (in /etc/resolv.conf). No need to mess with DHCP at
> all.

And what happens when the DHCP server assigns that address to someone else?
Also, IIRC some ISPs won't allow traffic from computers that don't have an
address currently assigned by the DHCP server.

James Knott wrote:

> And what happens when the DHCP server assigns that address to someone else?
> Also, IIRC some ISPs won't allow traffic from computers that don't have an
> address currently assigned by the DHCP server.

Let me clarify. I have a static, public, address which I pay through
the nose for from my ISP (comcast). The DHCP server that I've been
talking about is my router/NAT device/cable modem provided by comcast.
It assigns things for my local, private, network.

I was just concerned about the assignment of *private* addresses in
10.1.10.0/24. NATing will ensure that what leaves my network comes from
my properly assigned public IP address.

My router from comcast has its own DHCP server on it. I have limited
control over it. But I can (and have) specified the range of the
dynamic pool. So the internal machines that I am assigning statically
to private addresses are private addresses outside of the dynamic pool
range.

I hope this answers your concern. I am *not* trying to claim an IP
address to which I'm not routed for.

-j